House Speaker John Boehner stopped by the Hyatt Regency on Capitol Hill Thursday afternoon to pitch a gathering of the National Association of Manufacturers on the Republicans' plans for jobs and growth.

"While my colleagues and I don't have a majority here in Washington," the speaker vowed, "we're going to continue to pursue our plan."

Or will they?

Not an hour after those words were uttered, Boehner's House Republicans dealt him the latest in a series of humiliations. Sixty-two Republicans voted against the farm bill, defeating a major piece of legislation Boehner had made a test of his leadership by pushing for it publicly and voting for it personally.

The dispute this time was over food stamps and agricultural subsidies, but the pattern was the same: House leaders lost Democratic support by tilting the bill to satisfy the Republican base, but a group of conservative purists remained upset that the legislation didn't go far enough.

Much the same dynamic confronts Boehner as the House prepares to take up immigration legislation next month. A similar set of pressures has kept Boehner from negotiating a long-term budget deal with the White House.

In all instances, Boehner faces a choice: His job or his legacy. He can enact landmark compromises, but lose his job in a conservative coup. Or he can keep his job but get nothing much done.

With a few exceptions -- the "fiscal cliff" deal, Hurricane Sandy aid -- Boehner has chosen job security over achievement. He did it again on immigration, announcing that he doesn't "see any way of bringing an immigration bill to the floor that doesn't have the majority support of Republicans."

That promise puts him on a collision course with the Senate, where a fresh compromise on border security negotiated by Republican Sens. Bob Corker of Tennessee and John Hoeven of North Dakota make it likely that chamber's legislation, which includes citizenship, will have a large bipartisan majority.

Boehner's stance blocking an immigration compromise may preserve his speakership, but it would keep his party on what Sen. Lindsey Graham of South Carolina calls a "demographic death spiral" as Latino voters shun the GOP. Beyond the party, Boehner's position raises the likelihood of failure on another high-profile issue for a Congress that continues to reach new lows in public esteem -- Americans' confidence in Congress is at 10 percent, the lowest ever recorded for any institution.

And that was before the farm bill debacle.

The measure was never going to get much Democratic support because of $20 billion in cuts to food stamps. But Republicans lost what support they had on Thursday when they passed an amendment adding new work requirements to the food stamp program. That left only 24 Democrats on board.

The Agriculture Committee chairman, Frank Lucas of Oklahoma, pleaded on the floor for colleagues to "put aside whatever the latest email is" and vote with him. "And if you don't," he added, "they'll just say it's a dysfunctional body, a broken institution full of dysfunctional people."

After the bill went down, Majority Leader Eric Cantor came to the floor to blame Democrats, neglecting to mention the poison-pill amendment his Republican colleagues had passed.

Steny Hoyer, the minority whip, reminded Cantor that "25 percent of your party voted against the bill," and he invoked Newt Gingrich's 1998 speech deriding conservatives as "the perfectionist caucus."

Before the farm bill's collapse Thursday, Boehner said: "I didn't come here to be speaker because I needed a fancy title and a big office. I wanted to be speaker so I could do something on behalf of the country."

If so, he might reread Gingrich's speech.

Dana Milbank is a syndicated columnist. Follow him on Twitter@Milbank.