The unifying spirit of conservatives that will flow through the upcoming Conservative Political Action Committee - or CPAC -- conference in Washington will once again be interrupted by internal dissent caused by the high-profile participation of groups some find objectionable. Especially one group representing gay conservatives.

For the third consecutive year, leaders of the Family Research Council will not attend the gathering citing CPAC's expansive list of attendees, including members of the Republican gay rights group GOProud.

"There are those that really have agendas that are contrary to and stand in stark contrast to conservative principles that are actually co-sponsoring and helping to drive the agenda and that's problematic," FRC's Tony Perkins recently told Fox News. The group was a prominent feature of past CPAC meetings but Perkins is troubled by what he calls the event's "leftward drift" on core social issues.

Other conservative groups have also announced they're boycotting this year's event because of GOProud's role as a "participating organization" including the American Family Association and National Organization for Marriage.

"They have suddenly decided they would like to apply a litmus test to us [because we're gay] that they're not applying to other people," GOProud's Executive Director Jimmy LaSalvia told Fox Business Network in January.

This will be GOProud's second year at CPAC, and LaSalvia says their presence in Washington is "to promote conservative policies that are good for all Americans and we happen to think that includes gay Americans."

One of the leading agitators in the dispute is a group called American Principles Project which has equally praised or blasted various prominent conservative figures depending on their views.

"We applaud Senator [Jim] DeMint for taking a clear, uncompromising position on social issues of critical importance to conservatives," Andy Blom, APP's executive director said reacting to the South Carolina Republican's decision not to attend. In an email to Politico, DeMint's office implied the event wasn't "unified."

In turn, Blom took issue with CPAC organizers who've placed former Indiana Governor Mitch Daniels a choice speaking slot. The decision was "an affront to the millions of conservatives who believe that social issues such as abortion and traditional marriage are non-negotiable."

Even former Alaska Governor Sarah Palin isn't immune from APP's cutting critique after she endorsed the idea of an open dialogue at CPAC during an interview with CBN.

"The concern of conservatives is over the participation of a group whose stated goals run at odds with that of core conservative principles, not over debate over those issues," said APP President Frank Cannon who called upon Palin, who will not attend the event, to clarify her remarks. "The conservative movement at its strongest integrates its national security, economic and traditional values components," Cannon said.

This is the third year Palin has not accepted an invitation to speak at CPAC.

Chairman of the American Conservative Union and host of CPAC David Keene surprisingly stepped down from his post Wednesday. But there's no evidence that his resignation is directly tied to the ongoing controversy.

In addition to congressional leaders from Capitol Hill, at least 10 Republicans who may challenge President Obama in 2012 will address the convention.