After weeks of silence, Mr. Zuckerberg publicly defended his organization’s strategy in mid-June, calling it necessary and “unique.”

“That approach — of actually trying to work with people on both sides — is what makes us unique,” he wrote in response to questions on his Facebook page, adding: “And without bringing people in different parties and with different views together, meaningful reform will never happen.”

His office declined numerous requests for an interview.

The group has not revealed how much money it has raised so far, saying only that it is enough to make a difference in the process. Nor has it revealed any details on how it plans to sway the Republican-controlled House, except that it will back lawmakers who support a favorable immigration bill.

“I like to think we here in Silicon Valley have a different — and I hope, better — way of doing things,” Paul Graham, a venture capitalist and a founder of the technology incubator Y Combinator said about his hopes for Fwd.us.

This is precisely what complicates Fwd.us’s mission. Its principal constituents, the wealthy entrepreneurs of the valley, like to think of themselves as exceptional — except that some of its tactics have been criticized here precisely for reflecting an unexceptional Beltway approach.

In addition to the controversial ads, Fwd.us hired well-known Washington lobbyists. Its subsidiaries count political veterans like Haley Barbour, a former Mississippi governor and a Republican, and Joe Lockhart, a former spokesman for the Clinton administration, as board members.

Some Washington lobbyists say rewarding lawmakers with costly television ads could have unforeseen consequences for the industry, not least by considerably raising the price of influence.