The farm bill’s failings have been well documented. It is hugely expensive; it benefits wealthy farmers and agribusinesses already profiting from record high farm prices. It extends subsidies into new areas — fruits, vegetables, racehorses, salmon; further distorts markets — by diverting heavily subsidized sugar into heavily subsidized ethanol production, for example. It is so at odds with World Trade Organization rules as to invite retaliation against our exports.

Moreover, we don’t even know what all is in the massive bill. An alert watchdog group reports that a last-minute provision was secretly slipped into the bill nullifying an appeals court ruling ordering the U.S. Department of Agriculture to make public large quantities of data on how it administers billions of dollars in subsidies. Who knows what else is in there?

Urban and suburban lawmakers were not about to shower largesse on wealthy corporate farmers to make the package attractive. So two-thirds of the roughly $290 billion bill goes to fund popular nutrition programs — food stamps, emergency food aid, fresh fruits and vegetables for school children.

Of the three presidential candidates, John McCain flatly opposed the bill while Hillary Clinton and Barack Obama, who generally deride politics as usual, applauded this particularly shameless example of politics as usual.

President Bush, who caved on the 2002 farm bill, has decided to stick with his principles on this one and veto it for being bloated, wasteful and gimmick-ridden. All good reasons but it’s a little late in the game to start being principled. Better late than never, though.

Bush has opposed the bill all along, instead favoring a one-year extension of the old bill that would hand the problem to his successor, but he is up against a mass defection of his own Republicans.

The bill passed by convincingly veto-proof margins, 318 to 106 in the House with 100 Republicans in the affirmative and 81 to 15 in the Senate with 35 Republicans voting aye.

Considering the margins against him, President Bush’s veto may be only a symbolic gesture but one had should make anyway.