WASHINGTON -- House approval of a scaled-back farm bill is setting up what could be an even bigger fight over food stamps and the role of domestic food aid in the United States.

Food stamps have been a part of farm bills since the 1970s to gain urban Democratic votes for the rural measure. But that union has soured this year as the food aid has exploded in cost and House Republicans have taken aim at the program. Normally bipartisan, farm bills have become much less so.

Republican leaders in the House won passage of the smaller farm bill on a party-line vote Thursday by dropping a section of the bill that dealt with food stamps, saying they would deal with that issue in a separate bill. After rallying most of his caucus to vote for the farm portion of the bill, House Majority Leader Eric Cantor, R-Va., said Republicans would "act with dispatch" to get a food stamp bill to the floor.

It remained unclear what a food stamp bill would look like, how it would move through the House or how quickly lawmakers could craft a bill. While Democrats have opposed any cuts to the $80 billion-a-year program, designed to give people temporary food assistance when their income falls beneath a certain level, Republicans have proposed many different approaches to trimming it. The program has more than doubled in cost in the last five years as the economy faltered and now serves around 1 in 7 Americans.

Rep. Marlin Stutzman, R-Ind., has pushed the idea of a split bill for more than a year. A farmer, he has maintained that Congress should consider food stamps by themselves.

"By splitting the bill, we can give taxpayers an honest look at how Washington spends our money," he said.

If a bill to cut food stamps reaches the House floor, it could be the first major debate over the role of the program, now called the Supplemental Nutrition Assistance Program, or SNAP, in decades.

"I think there are some Republicans who think this is their moment to end this program as we know it, and the question is will they succeed or not," said Rep. Jim McGovern, a Massachusetts Democrat who has long championed food aid for the poor.

SNAP is available for people who meet certain income and asset tests. In April, more than 47 million people were using the program, including those in 23 million households. The average benefit is about $130 a month for an individual and around $270 for a household.

Proposals to reduce the program have ranged from what was in the original farm bill, a 3 percent cut and changes in eligibility, to an overhaul of the program that would take a fraction of the federal money now spent and give it to the states to administer. Others have proposed putting an expiration date on the program, which is now permanent, so Congress would have to take a look at it every few years.

Republicans have already supported an amendment to the original farm bill that would have put broad new work requirements on food stamps. Adoption of that amendment caused many Democrats to pull their support for the bill.

Democrats were angry, too, that passage of the pared-back bill appeared to set the stage for higher food stamp cuts in a separate bill. Several Democrats delayed the final vote by forcing procedural votes, and many came to the floor to denounce the legislation passionately.

House Minority Leader Nancy Pelosi, D-Calif., said to Republicans, "You are taking food out of the mouths of your own poor constituents."

Since the food stamp program doesn't expire, the program is untouched as long as no food aid cuts become law.

Anti-hunger groups are already mobilizing to deflect whatever Republicans propose.

"Republican leadership seems to be coming at the program with malign intent and that's deeply concerning," said James Weill of the Food Research and Action Center. He said they are hoping to rely on the Democratic-led Senate and President Barack Obama, who has also opposed food stamp cuts, to hold off against the House. The White House issued a veto threat against both bills.

A Senate farm bill passed last month would cut around a half a percent from the SNAP program.

The GOP caucus is divided over how much to cut. Many Republicans praised the 3 percent cut to SNAP in the original House farm bill and the changes in eligibility. But others said it didn't go far enough and voted against the bill, leading to the legislation's defeat.