* Ordinarily bipartisan, farm bill passes on party-line vote
* Republicans say they'll handle food stamps later
* White House threatens veto over food stamps, lack of farm reform
* House-Senate differences make compromise difficult (Adds analyst, farm group, lawmaker comments)
By Charles Abbott
WASHINGTON, July 11 (Reuters) - The Republican-controlled U.S. House of Representatives defied a White House veto threat and passed a controversial farm bill on Thursday that expands the taxpayer-subsidized crop insurance system but omitted food stamps for the poor.
Lawmakers passed the 608-page bill, unveiled by Republican leaders late on Wednesday, on a 216-208, party-line vote after two hours of debate in which no amendments were allowed. Twelve Republicans opposed the bill; no Democrat voted for it.
Republican leaders said food stamps, traditionally part of the farm bill, would be handled later and that, for now, they needed a way to start negotiations with the Senate over a compromise bill.
Democrats said the real intent of the action was to isolate food stamps for large cuts in funding. There is no timetable, so far, for a separate food stamp bill.
The bill was drafted to attract the support of fiscally conservative Republicans who helped defeat an earlier version on June 20, putting the measure in limbo and embarrassing the leaders who had backed it. But most major farm organizations as well as food stamp advocates opposed the strategy.
After passage by the House, the next step would be House-Senate negotiations over a compromise bill - a possible stumbling block.
Analyst Vincent Smith of Montana State University said fundamental differences between the House and Senate could prevent agreement on a bill that both chambers would support.
"You don't have a majority for anything you can put together," Smith said.
Food stamps were the headline issue, but there are disagreements on crop supports too.
The Senate proposed $4 billion in food stamp reforms while House Republicans were asking for at least $20 billion in cuts, the largest in a generation.
Senate Agriculture chairwoman Debbie Stabenow, a Michigan Democrat, said the House legislation "is not a real farm bill" but she would negotiate for a compromise. The Senate farm bill, which includes food stamps, saves $24 billion, compared with $13 billion in the House bill.
Frank Lucas, the House Agriculture Committee chairman, who pledged he would try to write a food stamp bill, said the vote on Thursday would put the farm bill back on track. "Give us a chance. Let the place work," said Lucas.
Senate Agriculture chairwoman Debbie Stabenow, a Michigan Democrat, said the House bill "is not a real farm bill" but she would negotiate with the House for a compromise bill. The Senate farm bill, which includes food stamps, saves $24 billion.
House Speaker John Boehner declined to say if leaders would allow a vote on a farm bill with larger food stamp spending than his party liked. "We'll get to that later," he told reporters.
Food stamps would remain in operation even if left out of the farm bill because the program is permanently authorized. But Bob Greenstein of the think tank Center on Budget and Policy Priorities said the House action showed the program was in danger of more spending cuts.
Massachusetts Democrat Jim McGovern said he believed conservatives were promised a chance to strive for deeper cuts to food stamps in upcoming legislation. The defeated earlier version of the farm bill would have ended benefits for 2 million people, or about 4 percent of recipients.
"A vote for this bill is a vote to end nutrition programs in America," said Rose DeLauro, a Connecticut Democrat.
House Democratic Leader Nancy Pelosi said: "You are taking food out of the mouths of your own poor constituents. What are you thinking?"
At latest count, 47.6 million people, or nearly one in seven Americans, received food stamps at an average of $132 a month, equal to $4.25 a day.
"Splitting the farm bill will hurt hungry and poor people," said David Beckmann, president of Bread for the World, a charitable organization devoted to ending hunger.
Enrollment has doubled since 2004 and the cost of the program, $74 billion last year, has tripled. Fiscally conservative lawmakers say the price tag is unbearable when the federal deficit must be reduced. Defenders say high enrollment reflects continued high jobless rates and slow economic growth.
In a statement late on Wednesday, the White House threatened to veto the House bill because it "does not contain sufficient commodity and crop insurance reforms" and omitted food stamps, formally named the Supplemental Nutrition Assistance Program.
"The Supplemental Nutrition Assistance Program is a cornerstone of our Nation's food assistance safety net, and should not be left behind as the rest of the Farm Bill advances," said the White House.
The House bill creates new programs to shield growers from downturns in crop revenue and expands the subsidized crop insurance program by 10 percent, or $9 billion over 10 years.
There was no expiration date on its crop supports so they could remain in effect for years to come.
The American Soybean Association said other important parts of the farm bill, such as soil conservation and farm export promotion, might be allowed to expire in five years because there would be no impetus to write a new comprehensive farm law.
The bill also includes a provision to delay implementation of a 2011 law that broadens food safety rules until the government carries out a study of the cost of compliance. (Reporting by Charles Abbott; Additional reporting by Richard Cowan; Editing by Ros Krasny, Tim Dobbyn, Gunna Dickson)