When the House overwhelmingly rejected his attempt to impose new accountability measures on the Obama administration’s Afghanistan policy earlier this month, leading liberal Rep. Jim McGovern took some solace in winning the support of Speaker Nancy Pelosi (D-Calif.).

The Massachusetts Democrat noted in a statement that his amendment to the war spending package earned the support of 60 percent of House Democrats, “including Speaker Pelosi, who by tradition rarely votes on the House floor.”

Indeed, when Pelosi stepped out to back the amendment, it was only the 33rd time this year that the top House Democrat had swiped her voting card. Out of about 1,400 votes so far this Congress, Pelosi has participated in just 81.

The numbers underline a frequently overlooked fact about the Speaker: Even as she has consolidated power in her office and emerged as her party’s most forceful advocate of far-reaching change, she has exercised some restraint on the floor.

The tack is apparently a nod to tradition. As presiding officer of the chamber, the Speaker is expected, for the most part, to abstain from voting.

But Pelosi herself has given varying explanations for it. Two years ago, she told Politico simply that “a Speaker doesn’t vote.” Asked at a roundtable with reporters in December how she would come down on a resolution to force a withdrawal from Afghanistan, she laughingly said she doesn’t vote “unless it’s a tie.”

“It’s just that usually I’m so busy that every now and then, I’ll see a suspension that’s, you know, motherhood, apple pie, children and everything, and I’ll say, ‘I wanted to vote on that,’ but I’m so busy that I didn’t even get a chance to,” she said.

Pelosi, who took the gavel in 2007, occasionally has found the time to register approval for those measures. In March, she joined 374 of her colleagues backing a resolution congratulating the New Orleans Saints on their Super Bowl win (only Illinois Republican Rep. Timothy Johnson opposed it). A month later, she joined a unanimous tribute to Polish plane crash victims.

And the California Democrat has made it a point to be counted on the signature items of her party’s agenda. That has included votes for the climate change package, health care reform, the Wall Street regulatory overhaul, the repeal of the military’s “don’t ask, don’t tell” policy, extensions of unemployment benefits and a tightening of campaign finance disclosure rules.

Democratic aides said the calculation is simple, if not always precise: The Speaker votes on long-standing personal priorities, major party initiatives and, occasionally, when she needs to.

But despite Pelosi’s joking suggestion that she only intervenes to break a tie, she has shown she prefers to avoid casting the deciding vote. In late June, as her team rallied to muster a majority for the financial reform conference report, the Speaker waited for the measure to gather 218 votes before she weighed in, casting the 220th vote for the package. It passed with 237 votes.

A similar scene unfolded earlier this spring, as Democratic leaders broke from a private huddle in the Speaker’s office just off the House floor to go work their colleagues during a vote on a Republican motion to recommit. As they made their way to the floor, Pelosi could be heard asking her second in command, House Majority Leader Steny Hoyer, whether she needed to vote. “I don’t think so,” the Maryland Democrat told her, and she didn’t.

Pelosi is a notably present figure on the floor, delivering far more frequent, and lengthy, speeches than her predecessor, Dennis Hastert. But she sidelines herself during votes more often than either of her two GOP predecessors, according to an analysis of figures from CQ. Three and a half years into her Speakership, Pelosi has amassed a participation record of about 8 percent. Over Hastert’s eight years in the post, the reserved Illinois Republican’s record was about 13.5 percent. And then-Rep. Newt Gingrich (R-Ga.) voted about 9.5 percent of the time he wielded the gavel.

Ron Bonjean, who served as a spokesman for Hastert, said the then-Speaker chose his spots strategically. “It was symbolic for House Members to see, and it raised the importance of the legislation,” he said. Voting or speaking too frequently diminishes the office, Bonjean said, adding that while Pelosi might abstain from voting, he believes she is too prominent in floor debates.

In sticking to a low-vote diet, Pelosi is following a long-standing historical precedent. The Speaker was only formally granted the same voting rights as other members in 1850, according to the Office of the House Historian. The Speaker’s name is not on the tally from which the yeas and nays are called during a roll-call vote — and only added to that list, at the end, at the request of the Speaker. During electronic votes, Pelosi has to direct the clerk to record her vote, then backs up the directive by submitting a voting card — a change to the rules made in 1990.

Steven T. Dennis and Rachel Bloom contributed to this report.