On Monday or Tuesday, the Senate is expected to vote on a massive five-year farm bill that will set the course of U.S. food policy for the next five years and cost $956.4 billion over the next decade.

We've already taken a detailed look at what's in the farm bill — from food stamps to crop insurance for farmers to conservation programs.

But we can also look at some of the major criticisms of the legislation, and why a number of groups, from fiscal conservatives to a few environmental advocates, are urging the Senate to vote "no." These critics probably can't derail the bill, which has wide bipartisan support in Congress, but it's worth hearing them out:

-- It's too expensive. The current farm bill was supposed to save money. Its backers in Congress are touting the fact that the legislation cuts $16.5 billion from the deficit over the next decade, compared with simply extending previous law.

But that's a relatively small trim compared with other proposals. In its 2014 budget, for instance, the White House had asked for farm legislation that would have saved twice as much, $38 billion — mainly by slashing payouts to farmers.

What's more, as Ryan Alexander of Taxpayers for Common Sense laments, no one's sure that those projected savings will even materialize: The Congressional Budget Office estimates that two-thirds of the deficit reduction won't happen until after 2019 — after this bill expires — and that depends on economic assumptions that may not pan out. About the only guaranteed cut here is the $8.4 billion snip to food stamps.

 -- The subsidies to farmers may go up, not down. The current farm bill was also supposed to overhaul the way the federal government supports farmers. But there's a lot of debate about whether the new system is actually an improvement.

(AP Photo/Ed Andrieski, File)

Some background: In previous farm bills, Congress would pay landowners fixed sums per acre, regardless of whether crop prices rose or fell — or even whether they planted at all. But these "direct payments," which were costing $4.5 billion per year, had become untenable politically.

So, in the latest farm bill, lawmakers scrapped the direct payments entirely. Instead, they expanded the system of subsidized crop insurance to protect farmers from sudden price drops. The bill would also cap how much money an individual farmer can receive — $125,000 annually. (Lawmakers rejected amendments that would have shrunk this to $50,000.)

In theory, the extra subsidies for crop insurance are supposed to cost less than the old direct payments did. But, again, it depends. More droughts or unseasonable cold weather could cause these payments to soar unexpectedly. Likewise, the new "shallow loss" insurance programs could start paying a lot of money if the price of commodities like corn and soy start dropping from their recent highs. "In fact," argues the R Street Institute, "given recent drops in the price of corn, the shallow loss program would be triggered on day one for the nation’s largest commodity crop."

Critics have also complained that too many larger, wealthier farmers benefit from the subsidies. People making up to $900,000 per year in adjusted gross income can qualify. It's also possible that absentee investors could still receive federal money (the subsidies are only supposed to go to those "actively engaged" in farming, but it's unclear how this language will be interpreted by regulators)."The final bill," says the Environmental Working Group (EWG), "fails to include a means-testing provision that reduces insurance subsidies for the largest producers."

Note: There's also an important environmental angle to crop insurance, although conservationists are much happier with how this unfolded. Farmers now have to implement basic soil and wetlands protections to qualify for insurance support. That's a big change. Likewise, critics have long argued that subsidized crop insurance allows farmers to expand onto marginal lands that should be conserved, such as fragile grasslands. But this farm bill now contains a "Sodsaver" provision that limits subsidies for farming on these lands in the Midwest.

-- The bill cuts food stamps. The new farm bill would also cut spending on food stamps by $8.4 billion over 10 years through a variety of tweaks. For instance, new rules would prevent some 17 states from using their home-heating programs to boost eligibility for food stamps (the s0-called "heat-and-eat loophole"). The bill would also clarify rules to ensure that, say, college students or lottery winners couldn't qualify.

This cut is far smaller than many conservatives wanted — House Republicans, for instance, were originally angling for a $40 billion cut, by restricting eligibility for childless working adults and other recipients. They didn't get their way.

On the flip side, a few liberal groups (and lawmakers) are opposed to these scaled-back cuts — particularly at a time when agricultural companies and wealthier farmers might end up with more generous handouts. "Only in Washington could a final bill that doubles the already egregious cuts to hungry families while somehow creating less total savings than originally proposed be called progress," said Sen. Kirsten Gillibrand (D-N.Y.) last week.

-- Miscellaneous criticisms. A few industry groups also aren't happy with select aspects of the bill. The meat industry, for one, is opposed to mandatory "country of origin labeling" rules that would require meatpackers to label where animals were born, raised, and slaughtered. (They say this could raise costs.) And some farmers will likely lose out in the shift from direct payments to crop insurance, like Southern rice farmers or peanut growers.

Even so, the bill still has plenty of supporters: That all said, many observers think the bill has enough support to sail through the Senate and become law. It already passed the House, in part because it picked up more Democratic support this time around — thanks to the fact that the food-stamp cuts were less severe than first envisioned and the fact that dairy farmers were protected against losses.

The Senate is expected to be a similar story. Farmers and agribusinesses, by and large, support the new crop insurance system. And hundreds of conservation groups, including the National Wildlife Federation and Nature Conservancy, favor the bill's protections for water and soil. (They also note that conservation funding would shrink dramatically if no bill passes at all, whereas crop insurance would still continue apace.) See Jerry Hagstrom in the National Journal for a good rundown of the politics here.

Further reading: The $956 billion farm bill, in one chart.