Rep. Tom Cotton (R) looks like he’s in decent shape in Arkansas’ U.S. Senate race, despite his record and platform, with most recent polling showing him with a slight edge over incumbent Sen. Mark Pryor (D).

That doesn’t mean, however, that Cotton’s limited voting record after 20 months in Congress can’t trip him up.

The Arkansas Republican, one of the year’s most far-right candidates for statewide office, has been pressed to explain all sorts of House votes – his opposition to disaster relief aid, his vote to privatize Medicare out of existence, etc. – but it’s the Farm Bill that’s arguably the most problematic. Arkansas’ farms and state economy rely on this important agricultural legislation, and the fact that Cotton tried to kill it reinforces Pryor’s argument: the congressman’s agenda is just too extreme for Arkansas.

What’s more, Arkansas’ House delegation has four Republicans, and the other three voted for the Farm Bill, making Cotton appear that much more extreme and out of step – even within his own Republican Party, even among GOP lawmakers from the Deep South.

In July, the far-right congressman came up with a defense: he couldn’t vote for the Farm Bill, Cotton said, because it should have done more to treat food-stamp recipients as suspected drug addicts

It was a plainly dumb thing to say, so now Cotton is rolling out a new defense in a television commercial . In it, after noting that his father has a farm, the congressman tells viewers:

“When President Obama hijacked the Farm Bill, and turned it into a food-stamp bill, with billions more in spending, I voted, ‘No.’”

By any fair standard, Cotton is simply lying. It’s a risky thing to do for a candidate a small lead in the polls and only seven weeks left in the campaign, but apparently, the congressman sees it as a necessary risk.

For those unfamiliar with the Farm Bill, it used to be one of the easier pieces of legislation to pass. Democrats supported provisions that help feed low-income Americans; Republicans supported elements that extend subsidies to agribusinesses; and the result has traditionally been a package that sailed through the House and Senate without much fuss.

This context is important because it underscores one of Cotton’s more obvious falsehoods: “President Obama,” the congressman claims, turned the Farm Bill “into a food-stamp bill.” In reality, it started as a food-stamp bill many years before Obama arrived in Washington.

In the most recent fight over the Farm Bill, Senate Democrats reached a compromise with the GOP-led House on an agricultural package that cut federal spending by about $23 billion. This, naturally, leads to the second Cotton falsehood: Obama, the congressman said in the ad, added “billions more in spending” to the legislation.

I suppose if Cotton aides want to stretch the truth past the breaking point, the House-Senate compromise included more spending than the House Republican version, but when a congressman says legislation has “billions more in spending” when it actually cuts billions in spending, he simply isn’t being truthful with the public.

Finally, none of this had anything to do with the White House, which leads us to Cotton’s third demonstrable falsehood. In no version of reality did President Obama “hijack” the legislation – the House passed a ridiculous version of the Farm Bill that Republicans knew would never become law, which led to negotiations, and ultimately, a bicameral compromise. If Cotton didn’t like that compromise, here’s his opportunity to explain why.

Unfortunately, however, the congressman has instead decided to mislead the public in a rather brazen way. It suggest Cotton believes the truth isn’t good enough, so he has to resort to deception.