mccain_060009.jpg, originally uploaded by amanda koster.

Today’s Republican presidential debate in New Hampshire comes at a time when many conservatives are distracted by the immigration debate taking place in Congress. While some candidates, such as Tom Tancredo and Duncan Hunter, are bound to seize on the issue tonight, the most interesting man to watch will be John McCain, who has staked out an unpopular position alongside the Bush Administration.

Since the bill was introduced two weeks ago, McCain has seen his poll numbers take a hit. (Ryan Sager has a good recap of the latest numbers, which put McCain in fourth place.) As Chris Cillizza reported last week, McCain’s response was to ratchet up the the rhetoric. He did so again today. And I’d venture to guess that he’ll continue to pick a fight with conservatives tonight.

The most interesting number that Sager makes note of is the 51% of Arizona voters who have an unfavorable view of McCain in the wake of the immigration deal. Fellow Arizona Sen. Jon Kyl has also suffered as a result of his association with the agreement.

During a conference call organized by Mitt Romney’s campaign at 3 p.m. today, I asked former Sen. Jim Talent and former New Hampshire Attorney General Tom Rath just how much immigration has hurt McCain. (Romney and McCain have clashed recently on the issue.)

Rath said the issue plays to Romney’s advantage because it shows how he approaches a problem. Talent played down it’s impact, saying, “Romney’s support has been growing for some time long before the immigration bill was introduced.”

Both operatives said that while immigration would certainly play a larger role in tonight’s debate, they didn’t want it to dominate as the issue or the Iraq War overwhelmed everything else at Sunday’s debate among Democrat candidates.