'Trump before Trump:' Obama goes after old nemesis on the campaign trail

As the former Republican chairman of the House Oversight Committee, Rep. Darrell Issa made made things pretty hard on the Obama administration, with investigations into the Benghazi attack, political favoritism at the Internal Revenue Service and Obamacare.

Obama came to Issa's backyard Sunday night to return the favor..

At a fundraiser for Issa's Democratic opponent in La Jolla, Calif., Obama laid into Issa with an intensity usually reserved for Republican presidential nominee Donald Trump.

After all, Obama said, Issa was "Trump before Trump."

"This guy has spent all his time simply trying to obstruct, to feed the same sentiments that resulted in Donald Trump becoming their nominee," accusing Issa of launching "trumped-up investigations that have led nowhere."

Prep for the polls: See who is running for president and compare where they stand on key issues in our Voter Guide

"Here's a guy who called my administration perhaps the most corrupt in history — despite the fact that actually we have not had a major scandal in my administration," Obama said.

Controversy drives money into Darrell Issa's campaign

Obama was particularly upset by a recent Issa campaign mailer showing a photo of Obama signing a bill into law, and noting that Issa co-sponsored the Survivor's Bill of Rights that Obama signed. Obama called it "shameless."

"And this is now a guy who because poll numbers are bad has sent out brochures with my picture on them touting his cooperation on issues with me," he said. "That is the definition of chutzpah."

But Obama did give Issa backhanded credit for one thing: He is "very pleasant to me at our Christmas parties."

Obama spoke to a fundraiser of about 60 people for the Democratic Congressional Campaign Committee, which is supporting Issa's opponent, Doug Applegate.

Issa responded that it's hard to argue he's done too much to hold Washington accountable.

“I’m disappointed but not surprised that the president, in a political speech, continues to deny accountability for the serious scandals that happened under his watch where Americans died overseas and veterans have died here at home," Issa said in a statement through his congressional office. "I’ve worked with the administration on good legislation where it was possible, called out wrongdoing wherever I saw it, and will continue to do so.”