President Barack Obama and Congressional Republicans are locked in a legal showdown over recess appointments that touches on Constitutional issues at the heart of how the U.S. government is designed.

But behind the headlines, a set of lawmakers have been dutifully gaveling in and gaveling out the pro forma sessions that had, until Jan. 4, kept recess appointments at bay.

Though the sessions, which can last as little as 30 seconds, are not exactly time consuming, they tend to come during weeks when the rest of official Washington is gone, making the job a lonely one.

The August recess and the days around Christmas are particularly unpopular times to occupy the Capitol, but a few lawmakers, often those whose districts are close to D.C., have volunteered.

“I think Members see it as a way to be a good team player and a relatively easy way to build rapport with leadership,” said a House aide whose boss has presided over several pro forma sessions.

Rep. Andy Harris (R-Md.) has been a standout, (briefly) wielding the Speaker’s gavel for pro forma sessions at least six times since June, when the House GOP began mimicking a strategy first devised by Senate Majority Leader Harry Reid (D-Nev.) during the George W. Bush administration to block recess appointments.

“Andy has been so great at being kind of, I guess you could say a relief pitcher,” said Rep. Jeff Landry (R-La.), who is partly responsible for filling the schedule of who will preside over the sessions.

On March 27, Obama issued 15 recess appointments, including for former AFL-CIO lawyer Craig Becker to the National Labor Relations Board, a pick that had stalled in the Senate.

Speaker John Boehner (R-Ohio) and Senate Minority Leader Mitch McConnell (R-Ky.) were eyeing strategies to prevent recess appointments, and a group of Senators proposed a solution.

“Sen. [David] Vitter [R-La.] and Sen. [Jim] DeMint [R-S.C.] and about 20-something other Senators sent us a letter which pointed out a provision in the Constitution that says, ‘listen, if you don’t recess, we can’t recess.’ So if we can’t recess, he can’t make those appointments. Basically pulling the same play out of Harry Reid’s playbook,” Landry said.

Landry organized 77 freshmen to sign a letter vowing they would assist GOP leadership in showing up for the sessions, and Boehner took Landry up on the offer.

“After we sent the letter to the Speaker’s office, they contacted us and said, ‘Listen, we think this is a great idea. But, you know, if you want this, you’re going to have to be willing to help us out in organizing the schedule,’” Landry said.

Enter Harris, who, given the proximity of his home to the Capitol, was happy to help. “If we’ve had some trouble filling the schedule, Andy always said, ‘Look, just call me,’” Landry said.

“If there’s no traffic, it’s about an hour and a quarter” to drive in, Harris said. “When I preside, I usually ask them not to schedule them for 10 a.m., because I know I’d be driving through rush hour, certainly on the Baltimore end.”

“Obviously, freshman Members aren’t going to chair major committees, aren’t going to serve major roles. But this is one way that you can do something for the team that helps them out,” Harris said.

On one occasion, Harris’s proximity prevented a parliamentary problem. The Member scheduled to preside couldn’t make it, and Harris was forced to cancel a district event and rush to the Capitol.

Though Harris has presided over the most pro forma sessions in the 112th Congress, the cast of lawmakers willing to preside over an empty House floor is surprisingly diverse, geographically speaking.

Freshman Rep. Jeff Denham, from far-away California, has gaveled three of the sessions in and out. “He’s taken an interest in these recess appointments,” Landry said.

And a cast of Ohioans, including Reps. Steven LaTourette, Steve Stivers and Jim Jordan, have reported for duty as well.

The strategy of pro forma sessions to block recess appointments originated with Reid in the Senate. So on the other side of the aisle, the self-sacrificing Members tend to come from the upper chamber.

In 2007, Sen. Jim Webb (D-Va.) took Christmas duty, presiding over pro forma sessions on Dec. 21, 23 and 26. “I strongly believe in the U.S. Senate’s constitutional oversight role,” he said in a release at the time.

Sen. Jay Rockefeller (D-W.Va.) was on Christmas duty in 2008 and Sen. Benjamin Cardin (D-Md.) was a big help during that year’s August recess, presiding over several sessions.

On the House side, Maryland Reps. Chris Van Hollen and Donna Edwards have helped preside over short sessions during recess, as has Virginia Rep. Jim Moran, when Democrats controlled that chamber.

And it’s been Edwards and Moran who have led Democrats’ protests in past weeks as they clamor for Congress to extend the payroll tax holiday.

When she came into the Capitol on Jan. 6, Edwards said, “I thought it was a work day,” a point somewhat deflated when a reporter noted she was familiar with the process having presided over pro forma sessions when her party was in power.

“Obviously, there are never more than a handful of Democrats in town to quote-unquote do the work,” Harris said.

But Democrats point out Republican ironies as well.

When Rep. Diane Black (R-Tenn.) introduced a resolution Tuesday criticizing Obama’s recess appointment, she urged the House to consider the measure “as soon as we return to Washington so we can send a message to President Obama.”

“The Congresswoman is so upset, she’s demanding action on her nonbinding resolution just as soon as she and her colleagues get back from vacation,” said a Democrat close to the Obama administration.