Thompson, who first endorsed Hoffman last month, has recently been joined by Minnesota Gov. Tim Pawlenty and former Alaska Gov. Sarah Palin in endorsing him over the Republican Party nominee, Republican State Assemblywoman Dede Scozzafava. The election, which happens a week from today, is being held up as a case study of the current conflict within the Republican party.
"Big government, high taxes, deficits, broken promises -- America is in trouble," Thompson says in the ad. "So when your grandchildren ask you why you didn't do something, be able to tell them that you voted for Doug Hoffman."
Local Republican representatives chose to back Scozzafava for her political experience and commitment to family values, even though she goes against the party on some social issues like abortion. Conservative activists, however, are getting behind Doug Hoffman. The split among conservatives has left their Democratic opponent, Bill Owens, in the lead in the most recent non-partisan poll of the race.
Former Republican House Speaker Newt Gingrinch, who is also considering a 2012 presidential run, is supporting Scozzafava, arguing that Republicans need to welcome in more moderates.
"This idea that we're suddenly going to establish litmus tests, and all across the country, we're going to purge the party of anybody who doesn't agree with us 100 percent -- that guarantees Obama's reelection," Gingrich said on Fox News Tuesday night. "That guarantees Pelosi is Speaker for life. I mean, I think that is a very destructive model for the Republican Party."
More on the race from CBSNews.com: