Over the past 50 years, many of the most successful, celebrated and even reviled politicians have remade themselves, sometimes as a reaction to changing political realities, sometimes because of personal or ideological epiphanies and sometimes because of a mixture of the two.

In settling on a top-10 political makeovers list, Roll Call decided to go by the old adage, “Politics is perception.” Many of the individuals on this list — such as President Lyndon Johnson, Sen. Strom Thurmond (R-S.C.), Sen. Robert Byrd (D-W.Va.) and Sen. Robert Kennedy (D-N.Y.) — were transformed personally and politically by the civil rights movement of the 1960s as well as the domestic turmoil created by the Vietnam War.

A few of our experts argued that some of the people on the list, such as former Sens. Barry Goldwater (R-Ariz.) and Wayne Morse (Ore.), remained consistent throughout their political careers. Still, Roll Call found ample evidence that political observers of their times perceived their actions as dramatic changes that carried significant political risks.

Certainly, the political evolution of former presidents like Ronald Reagan and Jimmy Carter could have easily made the list; however, we limited the candidates to those who have served in Congress at some point in their careers. We also excluded individuals, such as Sens. Trent Lott (R-Miss.) and Hillary Rodham Clinton (D-N.Y.) who appear to even now be in the midst of their own political transformations.

For this story, Roll Call consulted a number of historians, political scientists and longtime observers of the institution, including American University political scientist James Thurber, Boston University political historian Julian Zelizer, Assistant U.S. Senate Historian Betty Koed, Roll Call Executive Editor Morton M. Kondracke, along with numerous political biographies and other historical texts and articles.

Lyndon Johnson (D-Texas)
House 1937-1949, Senate 1949-61, Vice President 1961-63, President of the United States 1963-69

The cornerstone of Johnson’s political evolution was his decision to support equal civil rights for black Americans, and because he held such powerful positions in Congress and as president, his transformation also changed the nation.

With that single decision, Johnson “moves from being the prototypical Southern Democrat … into the great champion of liberalism in the 1960s,” Zelizer noted.

In the Senate, Johnson had been instrumental in watering down civil rights legislation passed in 1957, and much of his rise to power in the chamber can be attributed to his loyalty to Southern Democrats on the issue. Even the liberal Americans for Democratic Action accused Johnson of “betraying the Democratic party’s traditional claim to be the party of the people,” according to Robert Caro’s “Master of the Senate.”

But after he became president, the man who called civil rights legislation “a farce and a sham” in 1948 would bar the release of that same speech, in which he had also boasted of voting against an anti-lynching bill, according to Caro.

His role as a champion of the 1964 Civil Rights Act changed the makeup of the Democratic Party and caused many Southern Democrats to switch to the Republican Party.

As he famously told his aide Bill Moyers after signing the 1964 Civil Rights Act, “I think we just delivered the South to the Republican Party for a long time to come.”

Johnson also built a decidedly more liberal legacy as president by spearheading the creation of Medicare and other quasi-socialist programs under his plan for “The Great Society.”

Wayne Morse (Ore.)
Republican, an Independent and a Democrat in the Senate, 1945-1969

There’s no doubt that Morse was always a political maverick, but his decision to make not one, but two, party switches during his Senate career displayed an unparalleled willingness to take politically risky moves.

Morse was hardly your typical Republican when he ran for the Senate in 1944, having been a fan of Wisconsin progressive Robert LaFollette. But at that time, winning the Republican primary in Oregon made most politicians a shoo-in for election, according to Mason Drukman, author of “Wayne Morse: A Political Biography.”

Once in the Senate, Morse broke from his party in 1953 to become an Independent, largely because of what he saw as the rightward tilt of Republican President Dwight Eisenhower. His decision evenly split the Senate between Democrats and Republicans, but he helped Republicans retain control over the chamber even as he staged a stunt in which he brought a folding chair onto the Senate floor and placed it in the center aisle for two days.

Still, as Drukman said in an interview, Morse’s decision to become an Independent was an “enormous risk … and he lost an enormous amount of support” in Oregon. He also lost all of his influential Senate committee spots because of the switch.

Still, Morse’s conversion appears somewhat politically prescient because “at the time he turned Independent, there was a Democratic revolution in Oregon and he was the leader of that,” noted Drukman. Morse finally switched to the Democratic Party in 1955, giving Democrats a one vote majority.

Morse made his mark on the Senate by being an outspoken critic of both Sen. Joseph McCarthy’s (R-Wis.) anti-communist investigations and the Vietnam War. He lost his 1968 bid for re-election to Republican Bob Packwood.

Robert Byrd (D-W.Va.)
House 1953-59, Senate 1959-present

In his more than five decades in Congress, Byrd has transformed himself from conservative Southerner opposed to civil rights to a hero of modern anti-war liberals.

A member and organizer for the Ku Klux Klan in the 1940s, Byrd famously filibustered the 1964 Civil Rights Act for 14 hours. He also consistently supported the Vietnam War under both Presidents Lyndon Johnson and Richard Nixon.

When Byrd’s name was floated in 1971 as a potential Supreme Court nominee, Time magazine wrote that Byrd “has a less than statesmanlike record in the Senate … and is noted for his ‘industry’ rather than his legal erudition or constitutional insight.” But despite his conservative record, Byrd turned himself into a master of Senate procedure, whose political leanings by 1976 were “mainstream enough to be elected Senate majority leader,” according to a May 24, 2003 profile in The Washington Post.

Three decades later, Byrd is known at the “Dean of the Senate” and an expert on the U.S. Constitution. He also has become one of the most celebrated opponents of the current Bush administration, particularly the White House’s approach to the current war in Iraq. His February 2003 Senate floor speech decrying Bush’s plans to go to war became an international sensation among antiwar activists.

Barry Goldwater (R-Ariz.)
Senate 1953-65, 1969-87

Goldwater was a seminal figure in U.S. political history, helping to shift control of the Republican Party from liberal-minded Northeastern Republicans to more conservative and rural-oriented party that now dominates much of the Southern and Western United States.

Goldwater’s strong views that the federal government should not dictate to the states led to a 1964 presidential campaign in which he opposed the efforts of others in his party, as well as some Democrats, to force states to integrate public facilities and schools.

Still, many people blame his loss to President Johnson on his comments that appeared to endorse the use of nuclear weapons in Vietnam.

After returning to the Senate in 1968, Goldwater shed his reputation as a radical extremist and became the epitome of the respected elder statesman. In fact, his fellow Republicans in Congress picked Goldwater to tell President Nixon that he should resign in the wake of the Watergate scandal.

In the 1980s, Goldwater broke with Republicans as the religious right began to gain more influence with the party. In a 1994 article in The Washington Post, Goldwater complained about religious conservatives “who are trying to take the Republican Party away from the Republican Party and make a religious organization out of it. If that ever happens, kiss politics goodbye.” In the most dramatic example of his reversal on states’ rights, Goldwater got behind a movement in the 1990s to pass a federal law barring job discrimination against gays.

Strom Thurmond (S.C.)
Democratic South Carolina governor 1947-51, served in the Senate as a Democrat and a Republican 1955-56, 1957-2002

Thurmond’s political transformation closely tracked the South’s conversion from a bastion of the Democratic Party to the Republican stronghold it is today.

Thurmond began his political life as a “New Deal” Democrat, who as governor of South Carolina in the late 1940s pushed a measure to repeal the poll tax and required state prosecutors to pursue cases against white men accused of lynching blacks. But Democratic President Harry Truman’s call for broad civil rights legislation in 1948 spurred Thurmond to run against him as a “Dixiecrat” with a pro-segregation platform.

While he remained a Democrat as he entered the Senate in 1955, Thurmond found himself increasingly estranged from other Democrats in their push for civil rights and more government intervention in citizens’ economic problems. Despite being told by South Carolina political advisers that he could not get elected as a Republican, Thurmond, in 1964, became one of the first Southern Democrats to abandon his party in the wake of the civil rights fight.

An adept political animal who would become the longest-serving and oldest-sitting Senator, Thurmond’s party conversion was not his only political makeover. Despite his attempts to prevent civil rights legislation from passing — he still holds the record for the longest filibuster against the 1957 civil rights bill — Thurmond went on to support the creation of a national holiday to honor civil rights leader Martin Luther King Jr. and backed increased funding for historically black colleges.

Charlie Goodell (R-N.Y.)
House 1959-68, Senate 1968-71

Initially a supporter of the war in Vietnam and an opponent of President Johnson’s anti-poverty programs, then-Rep. Goodell was chosen by New York’s Republican Gov. Nelson Rockefeller to replace the late Democratic Sen. Robert F. Kennedy, because Goodell was a “moderate conservative from upstate” who “would provide a sounder balance” to the more liberal New York Republican Sen. Jacob Javits (N.Y.), according to a Sept. 13, 1968, Time magazine report.

But in the Senate, Goodell abandoned his well-known conservative streak and became not only a critic of President Nixon’s economic and criminal justice polices but also one of the most outspoken Republican opponents of Nixon’s handling of the Vietnam War. Goodell’s stance so enraged the Nixon White House that Vice President Spiro Agnew actively campaigned against Goodell in 1970.

Agnew excoriated Goodell for flip-flopping on the Vietnam War, calling him “the Christine Jorgensen of the Republican Party.” (Jorgensen was the first person to have a successful sex-change operation.) With White House firmly against him, Goodell lost his race to Conservative Party candidate James Buckley.

Robert F. Kennedy (D-N.Y.)
Senate 1965-68

While living in the shadow of his older brother, the late President John F. Kennedy, Robert F. Kennedy had a reputation as “militant, aggressive, intolerant, opinionated, somewhat shallow in his convictions … more like his father than his brother,” according to Arthur Schlesinger Jr.’s “Robert Kennedy and His Times.”

That perception was backed up by Kennedy’s short stint as legal counsel for Sen. Joseph McCarthy’s (R-Wis.) anti-communist investigation in the 1950s and his zeal as attorney general for going after corruption in organized labor, a traditional Democratic constituency.

But following his brother’s assassination in 1963, Kennedy “transforms from Cold Warrior, brother of the president, lukewarm on civil rights and labor to icon of 1960s liberalism — the lost promise of that era for many Americans,” Zelizer said.

Once he joined the Senate in 1965, Kennedy became an ardent supporter of the so-called “war on poverty,” and in his 1968 presidential campaign, he was known as a champion of the poor and working class. Kennedy’s apparent inconsistencies in public life were famously captured by political cartoonist Jules Fieffer in the 1960s as he depicted two Bobbys, “The Good Bobby” who championed civil rights and opposed the Vietnam War and “The Bad Bobby” who authorized wire taps on civil rights leaders and acted as JFK’s hatchet man.

Jim Jeffords (Vt.)
Republican in the House 1975-89, served as a Republican and an Independent in the Senate 1989-present

Jeffords stunned the country in 2001 when he decided to abandon the Republican Party and become an Independent caucusing with Democrats. Unlike most party switchers of the past, Jeffords’ move eliminated Republican control of a governmental trifecta — the House, the Senate and the White House — by handing Democrats the one vote they needed to take over what was a Republican-led 50-50 Senate.

In the spring of 2001, Jeffords, who was then chairman of the Senate Health, Education, Labor and Pensions Committee, objected to being sidelined on the president’s signature education initiative, No Child Left Behind, and pushed to scale back Bush’s $1.6 trillion tax cut in order to pay for special education programs. As a result, the White House threatened political retaliation that could have adversely impacted Vermont’s all-important dairy businesses. It was then that Jeffords decried the “abuse of power” and switched parties.

While Jeffords always appeared uncomfortable toeing the GOP party line, he was a relatively reliable Republican centrist who voted close to 50 percent of the time, and occasionally more than 60 percent of the time, with his fellow Republicans on party line votes. Once he allied himself with Democrats, however, his true stripes emerged. He voted with Democrats 92 percent of the time in 2004, according to Congressional Quarterly’s “Politics in America.”

John McCain (R-Ariz.)
House 1983-87, Senate 1987-present

McCain’s first transformation came from his experience as one of the “Keating Five” — a fistful of Senators accused of intervening with federal regulators on behalf of Charles Keating Jr., a campaign donor and savings and loan operator.

Not long after the Senate Ethics Committee mildly rebuked McCain in 1991 for his role in the Keating Five scandal, the Arizona Senator wrapped himself in the mantle of campaign finance reform, saying that donors had too much influence over politicians. The issue made the otherwise reliable conservative and party loyalist persona non grata in some Republican circles.

But it wasn’t until McCain ran for president in 2000 that his most profound political transformation took shape. “I’ve always had this streak, but I would argue that the presidential campaign did make me more of a populist,” McCain told Congressional Quarterly in 2002.

Indeed, the man who rejected allegations of global warming suddenly was holding hearings illuminating the potential threat of climate change. McCain, who had consistently supported the Republican version of a so-called “patients bill of rights,” teamed up with liberal icon Sen. Edward Kennedy (D-Mass.) to write compromise legislation. Plus, he joined with Sen. Joe Lieberman (D-Conn.) on a bill to require criminal background checks on sales at gun shows, reversing his long-held stand for unfettered gun owners’ rights.

Meanwhile, McCain continued to be a thorn in newly inaugurated President Bush’s side, voting against his $1.35 trillion tax cut and the president’s attempt to allow oil and natural gas drilling in Alaska’s Arctic National Wildlife Refuge. Most recently, he defied the White House and his own party leadership by brokering a compromise with a handful of Democrats on their party’s use of the filibuster against Bush’s judicial nominees.

Zell Miller (D-Ga.)
Georgia governor 1991-99, Senate 2000- 2005

As a Georgia political figure for nearly 30 years, Miller personified the successful Southern Democratic politician — conservative enough to win the white vote with just enough of a liberal record on civil rights to get the black vote.

Miller was not just a populist Southern Democrat who championed several education initiatives and shied away from social issues. While his penchant for tacking to the right on criminal justice issues and welfare earned him the nickname “Zig-Zag Zell,” he was also a partisan firebrand ready to condemn what he considered Republican elitists.

As keynote speaker at the 1992 Democratic National Convention, Miller won rave reviews for his attack on the GOP: “We can’t all be born rich, handsome and lucky. And that’s why we have a Democratic Party.”

Yet, after being appointed to the Senate following the death of Sen. Paul Coverdell (R-Ga.) in 2000, the man who had ridiculed Republican President Ronald Reagan’s “trickle down” economics as a policy that “blew the deficit sky-high, drove poverty through the roof, and squeezed the middle-class like a lemon at a county fair” was one of the leading Democratic backers of President Bush’s 2001 $1.6 trillion tax cut. (Many Democrats had warned that Bush’s tax cut would have the same effect that Miller said Reagan’s policies had had.)

In 2004, Miller published his book “A National Party No More,” an invective against the modern Democratic Party, which he seems to believe has evolved into the party of the elitists. Despite his consistent refusal to change parties, Miller burned his last bridge with the Democratic Party by savagely attacking his own party’s presidential nominee, Sen. John Kerry (Mass.), as the keynote speaker at the 2004 Republican National Convention.