Correction Appended

In November 1978, Donna Summer topped the music charts with “MacArthur Park,” the original “Lord of the Rings” — the animated version — made a big splash at the box office and Johnny Carson dominated late-night TV. Jimmy Carter was president, Barack Obama was a senior in high school and Carl Levin had just gotten a big promotion from former president of the Detroit City Council to junior Senator from Michigan.

More than 30 years later, Levin, 75, is in his second tour as chairman of the Senate Armed Services Committee and is preparing for a tough two weeks of closed hearings on the defense authorization bill.

He has become known as a persistent, meticulous lawyer — most recently and most vividly in his widely publicized grilling of Goldman Sachs executives last month. As chairman of the Homeland Security and Government Affairs subcommittee on investigations, he put Wall Street on notice. Yet officials in the military world were also watching.

“Thank God it wasn’t us that day,” said an official in the Department of Defense’s legislative affairs office. “He had directed his line of fire at someone else.”

In 1978, Levin, then best known statewide as the younger brother of two-time Democratic gubernatorial nominee Sander Levin (now chairman of the House Ways and Means Committee), fought through a crowded primary in what was supposed to be an open-seat contest for the Senate. But when Republican Sen. Robert Griffin changed his mind about retiring and jumped back into the race, Levin defeated him with 52 percent of the vote.

Despite the facts that he had no military experience and Michigan isn’t known for its military installations, Levin was immediately assigned a seat on the Armed Services Committee.

“I wanted to learn more about the armed services,” Levin recalled last week. “I had never served, and I thought there was a big gap in terms of my background and, frankly, felt it was a way of providing service.”

Levin has used the opportunity to learn well. His hallmark is knowing a subject almost as well as the witnesses who appear before him in hearings. His method requires three simple steps, he said: knowing “a heck of a lot” about the subject, listening closely to spot evasions and asking the question again when necessary.

When Levin doesn’t have time to study up on the issues well enough, he’s not too proud to delegate to committee Democrats. Rhode Island Sen. Jack Reed, a senior committee Democrat and Army veteran who worked alongside Levin on an important (but ultimately failed) provision to redeploy troops in Iraq in 2006, said the chairman brings out the best in people.

“The thing about it is, we’ve worked together, and his questions are so good without being intimidating. It’s not like you’re being interrogated. You begin to think, ‘Gee, I never thought about that. Wow, that’s interesting,'” Reed said. “You know that’s going to happen, so you bring a little bit extra to the conversation.”

Over three decades, Levin has authored or co-sponsored a number of watershed bills. Several focused on curtailing defense-related spending, including the 2005 base closure process and the Levin-McCain measure last year that reformed military procurement.

“We really changed the way in which we do acquisition,” Levin said.

He added that working closely with ranking member John McCain (R-Ariz.) and committee Republicans to maintain the committee’s bipartisan history is one of his proudest accomplishments. Levin’s and McCain’s offices are in the same hallway in the Russell Senate Office Building, and they’re both also on the Homeland Security and Government Affairs committee. Levin said committee staff work together in a space that doesn’t separate Democrats from Republicans, and they travel together.

Yet Levin does have some regrets about his work on the committee.

“I think the major disappointments would relate to the way the Bush administration went to war in Iraq,” he said.

His failed efforts to urge multilateral cooperation through the United Nations, to fight claims that intelligence showed a connection between Iraq and the 9/11 attacks and to keep the Iraqi army together so it would be better able to take over later were particularly disappointing to Levin.

But Levin, who is already Michigan’s longest-serving Senator in history and isn’t up for re-election until 2014, has a lot left to do on the committee. He has been a forceful supporter of repealing the “don’t ask, don’t tell” policy that restricts openly gay soldiers from serving in the military, and he has aggressively defended President Barack Obama’s military nominees on the Senate floor.

Shepherding through this year’s defense authorization bill is the challenge that he’s focused on now. Confident the bill will make it through committee, he’s more concerned about the schedule on the floor.

“It’s going to depend, I think, on how complex the bill is,” he said.

Correction: May 24, 2010

The article incorrectly reported that Sens. Carl Levin (D-Mich.) and John McCain (R-Ariz.) jointly lead a Senate Armed Services investigations subcommittee. Levin is the chairman of the Permanent Subcommittee on Investigations in the Senate Homeland Security Committee, and McCain serves on that panel.