Speaking at CPAC today, conservative commentator David Horowitz attacked conservative activists Suhail Khan and Grover Norquist, claiming that Khan, with Norquist's aid, “infiltrat[ed]” CPAC, the Bush White House and the conservative movement on behalf of the Muslim Brotherhood.

We've seen the conservatives fall into disarray over the recent events in Egypt with some conservatives hopeful about the fall of Egyptian dictator Hosni Mubarak while others, led by Glenn Beck, engaging in bizarre conspiracy theories such as that the protests in Egypt are tied to the Muslim Brotherhood, progressives, Marxists, and others.

But this is a whole new level.

Khan spoke at two CPAC 2011 events. Khan is also a board member of the American Conservative Union, the group that organizes CPAC each year. Furthermore, according to his biography, Khan has “served as a senior political appointee with the Bush administration” and as “Policy Director and Press Secretary for U.S. Congressman Tom Campbell (R-CA).”

Horowitz claimed that Khan “used his offices in the Bush White House with Grover [Norquist's] support to carry water for the terrorist Sami Al-Arian.” Horowitz added that “over the last 10 years, the influence of the [Muslim] Brotherhood has spread throughout our government.” More about the charges against Khan can be found here.

The conservative crack-up appears to be gaining momentum.

UPDATE: Dave Weigel reports on Khan's response to Horowitz:

“These are old, tired, baseless attacks that have been debunked by reputable sources,” said Khan. “This is baseless, and they're coming from people who are becoming more and more marginalized.”

On Horowitz in particular: “I'm not surprised. This is a former communist who's still using Saul Alinsky tactics. A few years ago, I was supposed to be part of al Qaeda. Now it's the Muslim Brotherhood. It's whatever's in the news.”