In July 2007, Sen. David Vitter (R-La.), a family values conservative, found himself at the center of the “D.C. Madam” prostitution scandal and fighting for his political career.

But instead of joining the ranks of lawmakers driven from office by their own transgressions, Vitter mounted a quiet counteroffensive. He lowered his head and spent the past year and a half working to regain his reputation as a leading conservative voice and to position himself to run for re-election in 2010.

Colleagues and veteran GOP aides chalked up Vitter’s ability to weather the storm to a number of factors, including his strength as a legislator, his continued popularity in reliably Republican Louisiana and the Senate’s tradition of affording its Members political second acts.

“He’s very smart, and he’s got good political instincts and a sound philosophy. He just seems to work harder than most anyone else in the Senate,” said Sen. Jeff Sessions (R-Ala.), noting that over the past six months, Vitter has taken an increasingly public role in a number of legislative fights, such as last fall’s Wall Street bailout debate.

“I have observed he’s more and more in the forefront of big issues … he doesn’t seem to dwell on anything,” Sessions said.

Sen. Richard Burr (R-N.C.), who shares a spot with Vitter on Minority Whip Jon Kyl’s (R-Ariz.) whip team, said the scandal is no longer an issue for his Louisiana colleague, primarily because his constituents seemed to have moved beyond it.

“I think it’s a nonissue because the only ones that matter are Louisiana voters,” Burr said, adding that they have decided “it’s not a disqualifying issue.”

Almost two years ago, Vitter was identified as having been a client of the “D.C. Madam,” Deborah Jeane Palfrey, while he was serving in the House. In a press conference with his wife, Wendy, by his side, and later in a closed-door meeting with his Senate colleagues, Vitter acknowledged he had committed “a very serious sin.”

The controversy threatened to derail his young political career.

Although Vitter — in his first Senate term — quickly became the target of late-night talk-show jokes and snickers in the halls of the Senate, his colleagues largely stood by him. The Senate Republican leadership choose not to punish Vitter because he was not under indictment and his alleged use of the prostitution service had occurred prior to his time in the chamber. Individual Members were by and large also unwilling to cast him aside, saying that while they disapproved of his actions, they did not believe he should be punished.

Vitter’s initial forays onto the Senate floor in the days following the revelations were not marked by the same cold shoulders given to his then-colleague Sen. Larry Craig (R-Idaho), who pleaded guilty in Minnesota state court to charges relating to a gay sex sting in the Minneapolis airport.

Unlike Craig — whose repeated statements to the media continued to provoke headlines — Vitter took a much lower profile. For months, he shunned the media, avoided discussing the scandal and kept a low political profile in the halls of the Senate.

However, Vitter continued to play an active role in legislative activities under the radar — a decision that Republican Senators say greatly helped him work his way back into the public eye.

For instance, in the fall of 2007, Vitter led a floor fight on a drug reimportation amendment to the Health and Human Services spending bill, a move that brought him into conflict with a number of his Republican colleagues. Vitter supports the ability of citizens to import prescription drugs, and the amendment was designed to block the HHS Department from halting those activities. While the Bush administration and many within the Republican Party opposed it, Vitter successfully attached his language to the bill. He also took the lead in successfully rallying a number of Republican lawmakers to sign onto a letter urging then-President George W. Bush to veto the 2007 Water Resources and Development Act.

Similarly, in January of last year, Vitter worked with other Members of the GOP’s freshman class — lawmakers who have not yet faced a re-election campaign — on a floor campaign to outline health care reform options that they could support.

Then last summer, Vitter, whose state is considered an “oil patch” state because of its offshore drilling industry, took an active role in the GOP’s energy fight. At the time, Republicans were hoping to use the skyrocketing cost of gasoline as a wedge issue to help defend some of their most vulnerable House and Senate Members, as well as to bolster Sen. John McCain’s (R-Ariz.) presidential bid.

Senate Minority Leader Mitch McConnell (R-Ky.) and other party leaders made the issue a top priority, and lawmakers took to the floor to give speeches on the issue. They spent months hammering away at Democrats’ energy plans.

Vitter played an active role in those efforts, Republicans said, giving a number of high-profile floor speeches. In fact, Republican leaders at one point distributed copies of one of his speeches to reporters and bloggers as part of their messaging campaign.

Vitter was also tapped as one of the GOP’s primary opponents of the financial bailout bill that passed last year. When the Bush administration came to Congress earlier this month for additional funds, Vitter led Republican efforts to block it. While the release of remaining funds ultimately passed, the bulk of Republicans, including McConnell, sided with Vitter and voted to try to withhold them.

“The prescription drug thing was a pretty big deal,” one GOP leadership aide said, explaining that while Vitter may have sought to avoid making news politically, he was clearly unafraid to step into a very public fight over a hot-button issue.

Burr also said the way Vitter handled his personal controversy — coming clean to his colleagues and “making right with his family” — helped blunt any concerns lawmakers may have had.

“People took him at his word that this was a part of his life that if he could do it over, he would,” Burr said.

Burr and other Senate Republicans also noted that the chamber has a long history of giving Members a second chance.

“A lot of heavy hitters around here have flown awful close to the flame,” one GOP aide said, noting that McCain and Sen. Edward Kennedy (D-Mass.), two of the most successful legislators in modern Senate history, have suffered through far more serious scandals and gone on to mount viable bids for the presidency.

As a result, Members have not “in any way, shape or form let it affect their relationship with him,” Burr said, adding that “historically, if they did, this would be a pretty lonely place.”