(David Paul Morris/Bloomberg/Getty Images)

Facebook CEO Mark Zuckerberg is in Washington this week lobbying lawmakers in the House on immigration reform, but he acknowledged today that a political group he founded to support the issue, Fwd.us, has hit some snags in its foray into politics.

"There's been a lot to debug in terms of making this work," Zuckerberg said at a question and answer forum sponsored by "The Atlantic."

The group, supported by wealthy Silicon Valley types such as Yahoo CEO Marissa Mayer and Google CEO Eric Schmidt, got into some trouble with progressives after it launched ads intended to give Republicans who supported immigration reform political cover by praising them for their opposition to President Obama's health care law or supporting the expansion of the Keystone XL pipeline.

The strategy was panned as "counterproductive" by liberal groups like Moveon.org and Progressives United, which participated in a boycott of ads on Facebook.

Zuckerberg, a relative newbie to political lobbying, said the aversion to crossing party lines even on issues both sides support "shocked" him.

"We've tried to get senior folks from both parties to come together and there have been interesting realities of that I was kind of shocked about," he said. "A senior Democrat would never want to associate with something funding Republicans."

Though he and his organization are knee deep in the politics of immigration reform, Zuckerberg, who was dressed in his signature gray t-shirt, zipped up dark gray hoodie and blue jeans, wouldn't answer most questions that might hint at his political leanings.

Where does he fall on the political spectrum?

"It's hard to affiliate as either a Democrat or a Republican. I'm pro-knowledge economy," Zuckerberg replied after a long trailing answer on a host of other tangentially related subjects.

Who is the person he most looks forward to meeting while in Washington?

After another long pause: "That's dangerous," Zuckerberg finally replied.

Still, after meetings in Congress designed to gauge the temperature on immigration reform, Zuckerberg said he is "optimistic" about the prospects that the House will pass a bill.

"Folks in both parties seem like they want to by and large move things forward," he said.