No one in Washington much cares what House Democrats do these days. House rules tend to ensure that the main job of members of the minority is to show up, vote “no” and lose.

And in the next Congress, Democrats will have fewer House seats than they’ve had since 1930.

So not much notice was directed last week at Nancy Pelosi’s first major intraparty defeat since she became House Democratic leader in 2003.

Pelosi won that post by defeating colleague Steny Hoyer and has been winning fights ever since. Until now.

That defeat was the election by the Democratic Caucus of New Jersey’s Frank Pallone to be ranking minority member of the Energy and Commerce Committee over Pelosi’s choice, California’s Anna Eshoo.

The election was conducted by secret ballot, and the vote was 100-90.

Those numbers are a vivid contrast to the totals in what was probably the most dramatic leadership vote in the Democratic caucus, the contest for majority leader in 1976, 38 years ago.

The winner then was Texas’ Jim Wright, who’d go on to become speaker after Tip O’Neill retired 10 years later. The loser was California’s Phil Burton.

The vote was 148-147. Burton spent the rest of his life trying to track down those who had committed to him but cast their secret ballot for Wright.

Do the math. There were 295 House Democrats voting in the caucus that year. This year, 190.

There is a direct linkage between Phil Burton and Nancy Pelosi. Burton was succeeded by his widow, Salah Burton, who endorsed Pelosi as their successor in 1987.

Though he never reached the leadership heights Pelosi has, Burton played a critical role in changing the House.

For years, liberal Democrats had decried the seniority system, which automatically made conservative Southerners (and/or senile members) committee chairmen. There they could and did block liberal measures from coming to the floor.

After the big Democratic victory in the 1974 election, Democratic leaders conceded that the caucus could vote on chairmanships if a sufficient number of members signed petitions for such a vote.

Burton organized a drive to get signatures to challenge every chairman: Nothing personal, signers could tell chairmen; we just want everyone to get a vote.

Three chairmen were defeated, and the principle was established that the Caucus determined chairmanships. That principle was reaffirmed when Pallone won last week.

After their big victory in the 1994 election, House Republicans, led by Newt Gingrich, instituted a similar procedure.

Chairmen would be determined by the Republican Steering Committee, on which party leaders had a major share of the votes, and there would be a six-year term limit (occasionally waived) on chairmen.

Both reforms can be defended on legislative-process grounds. It makes sense for legislative committees to be run by members in line with the views of the majority of the majority party.

Another result: Members compete for elective chairmanships by raising money for colleagues, largely from Washington insiders.

That is, the reforms make the House more accountable to voters than the seniority system, but also more responsive to lobbyists.

Pelosi has worked the new system ably.

She has raised $400 million for her fellow Democrats. She supported campaign chairman Rahm Emanuel’s recruitment of moderates who matched their districts, which gave Democrats a House majority in 2006.

She saw to the ouster in 2008 of Energy and Commerce Chairman John Dingell, the longest-serving House member ever, in favor of her fellow Californian, Henry Waxman.

She rallied House majorities for the stimulus package in February 2009 and for cap-and-trade ( a favorite of Bay Area environmentalists) in June 2009. She pushed through ObamaCare in March 2010.

But in November 2010, Democrats lost 63 seats and their House majority. Democratic moderates virtually disappeared. Pelosi’s hold on the leadership remained strong. But this year she stumbled.

She pushed hard for Eshoo, a close friend, though Pallone had more seniority. Black Caucus members, many with seniority, didn’t like that. Some resented Pelosi’s refusal to allow a pregnant and disabled member to vote by proxy.

Burton’s reform made the House Democratic Caucus more liberal — but also much smaller. Now Pelosi’s grip seems to have weakened just a little.