Obama singled out Rick Perry yesterday at a California fundraiser.

They say the best defense is a strong offense. At a campaign fundraiser yesterday in California Obama started making good on the wide speculation that his most effective strategy in defending the White House in 2012 would be getting nasty on Republican candidates.

Perhaps acknowledging Rick Perry as the most formidable threat against him next year in his new role as Republican front-runner, the president took aim at Perry being a climate change denier even as his home state suffers through historic wildfires. Obama mocked Perry, calling him “a governor whose state is on fire, denying climate change,” implying he’s either a liar or blind with denial.

Picking on Mitt Romney, apparently Perry’s main rival in the race, will likely be considerably easier for Obama—he’ll just have to take a cue from former Republican opponent Tim Pawlenty and start calling his health care bill “Obamney care.”

But according to Huffington Post the president also took aim at the broader electoral base of Republican voters. “Obama poked at the audience reactions at recent GOP presidential debates, singling out those who cheered at the prospect of someone dying because he didn’t have health insurance – and those who booed a gay service member,” writes HuffPo. “That’s not reflective of who we are,” the president said.

The president is in Silicon Valley for fundraising events—and while he may have been right that booing gay soldiers and cheering for the sick to die isn’t reflective of who his audience was at the event, it’s certainly reflective of the conservative base. The Tea Party may be supposedly losing popularity, but it’s the only political group to co-sponsor one of the debates with CNN, and the crowd it drew dominated headlines for days with its death-cheering antics. At least partly, this is who we are.

“This [election] is a choice about who we are and what we stand for and whoever wins this next election is going to set the template for this country for a long time to come,” the president said. Obama has clearly shifted political strategy from championing compromise to drawing a line in the sand between himself and Republican opponents. With the election still 14 months away, this is bound to be a long, nasty campaign.