In Congress, it's a marriage of convenience.Food stamp policy has been packaged in the same bill with farm subsidies and other agricultural programs since the 1970s. It was a canny way of assuring that urban lawmakers who wanted the poverty program would vote for farm spending. That worked until this year, when conservatives balked at the skyrocketing cost of food stamps. In June, a farm bill that included food stamps was defeated in the Republican-led House because fiscal conservatives felt it didn't cut the program deeply enough. In response, GOP leaders split the food and farm programs in two. The House passed the farm version in July and the food stamp version on Thursday. Both passed with narrow votes. The House and Senate versions must be reconciled before the five-year farm bill can become law, and that won't be an easy task. Food stamps remain in the farm bill passed by the Senate. That bill made only a half-percent cut to food stamps and the Democratic-led Senate will be reluctant to cut more deeply or to evict the poverty program from its home in the farm bill. Obama supported the cuts in the Senate bill, but has opposed any changes beyond that. The White House threatened to veto the House food stamp bill. ___ WHAT NOW? The current farm and food law expires at the end of the month. If the two sides can't agree by then, a likely scenario, Congress could vote to extend the law as it is, at the expense of many planned updates to agricultural policy. There won't be much urgency to do that until the end of the year, when some dairy supports expire and milk prices could rise. Other farm supports won't expire until next year, but farmers have been frustrated with the drawn-out debate that has now lasted two years, saying they need more government certainty as they manage their farm operations.