WASHINGTON - Food stamps look ripe for the picking, politically speaking.

Through five years and counting of economic distress, the food aid program has swollen up like a summer tomato. It grew to $78 billion last year, more than double its size when the recession began in late 2007.

That makes it a juicy target for conservative Republicans seeking to trim spending and pare government.

But to many Democrats, food stamps are a major element of the country's commitment to help citizens struggling to meet basic needs.

These competing visions are now clashing in Congress.

The Republican-led House has severed food stamp policy from farm legislation, its longtime safe harbor. A group of GOP lawmakers is planning a separate food stamp bill that would cut the program by as much as 5 percent, or about $4 billion a year.

The Democratic-led Senate, meanwhile, has passed a joint farm-and-food-stamp bill bearing a more modest reduction of about $400 million annually.

The way the conflict is resolved could have a big impact on the future of food stamps.

From President Lyndon Johnson's vision of a Great Society to President Ronald Reagan's condemnation of "welfare queens" to President Bill Clinton's embrace of welfare work requirements, food stamps have been a potent symbol.

Partisans tend to see what they want to see in the program: barely enough bread and milk to sustain hungry children, or chips and soda, maybe even steak and illicit beer, for cheaters and lay-abouts gaming the system.

A look at the history and future of food stamps:

NO MORE STAMPS

These days, people in the nation's largest food aid program pay with plastic.

These special debit cards are swiped at convenience store or supermarket checkouts to pay for groceries. The cards can't be used for alcohol or cigarettes or nonfood items such as toothpaste, paper towels or dog chow. Junk food or high-priced treats are OK.

The first food stamps were a temporary plan to help feed the hungry toward the end of the Great Depression of the 1930s. The government subsidized the cost of blue stamps that poor people used to buy food from farm surpluses.

The idea was revived in the 1960s and expanded into a permanent program that sold food coupons to low-income people at a discount. Beginning in the 1970s, food stamps were given to the poor for free. Benefit cards began gradually replacing paper in the 1980s.

Food stamps aren't the government's only way to feed those in need. There are more than a dozen smaller programs, including the one for Women, Infants and Children, and free and reduced-price school lunches.

In 2008, food stamps were officially renamed the Supplemental Nutrition Assistance Program, or SNAP. But most people still know the name that's been familiar since 1939.

ONE IN EVERY 7 AMERICANS

In a nation of 314 million people, roughly 47 million are eating with food stamps each month.

Who are they? Children and teenagers make up almost half the rolls, according to the Agriculture Department. About 10 percent are seniors.

The vast majority don't receive any cash welfare. Many households that shop with SNAP cards have someone who's employed but qualify for help because of low earnings.

The average food stamp allotment is $133 a person per month. The monthly amount a family gets depends on the household's size, earnings and expenses, as well as changing food prices and other factors.

Households can qualify for help with earnings up to 30 percent higher than the federal poverty level, making the limit about $30,000 for a family of four this year. These households are limited to no more than $2,000 in savings, or $3,250 if there are elderly or disabled residents.

In addition, most states allow people to qualify automatically for food stamps if they are eligible for certain other welfare programs. Although food stamps are paid for with federal tax dollars, states administer the program and have some choices in setting requirements.

Able-bodied adults who aren't raising children are supposed to work or attend job training or similar programs to stay on food stamps more than three months. But work requirements across most of the nation have been waived for several years because of the high unemployment rate.

People who are living in the United States illegally aren't eligible for food stamps. Most adults who immigrate legally aren't eligible during their first five years in the country.

RISING LIKE YEAST

The cost to taxpayers more than doubled over just four years, from $38 billion in 2008 to $78 billion last year.

Liberals see a program responding to rising need at a time of economic turmoil. Conservatives see out-of-control spending, and many Republicans blame President Barack Obama. While seeking the GOP presidential nomination in 2012, Newt Gingrich labeled Obama the "food stamp president."

Some of the growth can be attributed to Obama's food stamp policies, but Congress' budget analysts blame most of it on the economy.

The big factors:

—The SNAP program is an entitlement, meaning everyone who is eligible can get aid, no matter the cost to taxpayers.

—Millions of jobs were lost in the recession that hit in 2007. Unemployment is still high, and many people who have jobs are working fewer hours or for lower pay than before, meaning more people are eligible.

—Obama's 2009 economic stimulus temporarily increased benefit amounts; that boost is set to expire on Nov. 1. Time limits for jobless adults without dependents are still being waived in most of the country.

—Food stamp eligibility requirements were loosened by Congress in 2002 and 2008, before Obama became president.

—Fluctuating food prices have driven up monthly benefit amounts, which are based on a low-cost diet.

FEWER TO FEED?

The number of people using food stamps appears to be leveling off this year, and long-term budget projections suggest the number will begin to fall as the economy improves.

Why is it taking so long? Although the jobless rate has dropped from its 2009 peak, it remains high, leaving a historically large number of people eligible for food stamps. Since the recession began, a bigger portion of people who are eligible have signed up for food stamps than in the past.

Many people who enrolled during the worst days of the recession still qualify for SNAP cards, even if they are doing a little better now. For example, they may have gone from being laid off to working a low-paying or part-time job.

The Congressional Budget Office predicts in about a decade the number of people using food stamps will drop to 34 million, or about 1 in every 10 people.

FOOD AND FRAUD

Abuse was a worry from the start. The 1939 food stamp program was launched in May and by that October a retailer had been caught violating the rules.

There's been progress along the way, especially after the nationwide adoption of SNAP cards, which are harder to sell for cash than paper coupons were. The government says such "trafficking" in food stamps has fallen significantly over the past two decades, from about 4 cents on the dollar in 1993 to a penny per dollar in 2008.

But many lawmakers say fraud is still costing taxpayers too much. Some people lie about their income, apply for benefits in multiple states or fail to quit the program when their earnings go up. Recipients must tell their state agency within 10 days if their income goes over the limit.

Some stores illegally accept food stamps to pay for other merchandise, even beer or electronics, or give out cash at a cut rate in exchange for phony food purchases, which are then reimbursed by the government.

FOOD AND FARMS

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 conservative members felt it didn't cut the program deeply enough.

In response, GOP leaders stripped food stamps out of the farm bill and tried again. That version narrowly passed the House on July 11, leaving food stamps in limbo.

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 Senate will be reluctant to cut more deeply or to evict the poverty program from its home in the farm bill.

The House and Senate versions must be reconciled before the five-year farm bill can become law.

WHAT NOW?

The current farm and food law expires in September.

If there's no agreement between the House and Senate on what to do about food stamps, Congress could vote to extend the law as it is, at the expense of many planned updates to agricultural policy.

Meanwhile, House Republican leaders say they plan to advance a separate bill to cut food stamps as early as next month. Their plan would find savings by tightening eligibility standards and imposing new work requirements. It also may require drug testing and bar convicted murderers, rapists and pedophiles from receiving food stamps.

But Democratic senators and Obama oppose substantial reductions to food stamps and likely would block them from becoming law.

Even if the Senate goes along with the House bid to remove food stamps from the farm bill, SNAP benefits would still be available for now.

While farm bills set food stamp policy, the money is paid out through annual appropriations bills that so far have left benefits intact.

But the appropriations process could be another opportunity for lawmakers determined to pluck savings from food stamps.