Congress did not take any action to "legalize" consumption of horse meat — which was never illegal in the first place — but did lift the funding ban in a spending bill that Congress passed in November, which Bishop supported. The idea was that in the absence of inspections, the industry had gone underground, with horses shipped to Mexico and Canada for slaughter, where they often face inhumane practices.

Demos's campaign produced a letter Bishop wrote to a constituent in 2010 advocating prison time for participating in horse-slaughter for human consumption under the Prevention of Equine Cruelty Act and calling them "majestic animals."

"I'm not a psychiatrist, so I don't know what the technical definition of a cry for help is, but this seems to be in that realm," said Bishop spokesman Jon Schneider. "I guess they're bored and having fun or something. It's just kind of lame."

Schneider called the Demos attack a cynical game, pointing out that voting against the bill would have meant voting against other important spending measures, such as funding for cancer research.

Demos spokesman Kevin Tschirhart shot back, calling it disgraceful for a member of Congress to imply that a political opponent needed psychiatric care and pointing out that Bishop could have pursued options other than to support the bill as it was.

"If Tim BishopTimothy (Tim) Howard BishopDems separated by 29 votes in NY House primary Flint residents hire first K Street firm House moves to vote on .1T package; backup plan in place MORE really cared about this, he could have introduced an amendment to remove the portion of the bill regarding horse slaughter. He didn't," Tschirhart said. 

Demos has been unable to attract significant attention or raise major dollars in his second bid for Bishop's seat. In 2010, he was defeated in the Republican primary by businessman Randy Altschuler, who came within 1,000 votes of defeating Bishop after a weeks-long recount.

Altschuler is also seeking a rematch in 2012 and had about $400,000 to spend on his campaign at the end of September. (Demos had about $75,000.) Internal polling released by Bishop's campaign in November suggested that Bishop might be in better shape heading into his 2012 reelection match than he was two years ago.

—This post was updated at 3:05 p.m. and 3:22 p.m.