Still nursing election wounds, soul-searching Republicans gathered Thursday at the first conservative casting call for the US presidential election in 2016, with the party divided over how to broaden its appeal.

Several prospective White House candidates including Senator Marco Rubio and Representative Paul Ryan lined up for a chance to address the Conservative Political Action Conference just outside Washington, as did Republican heavyweights Mitt Romney and Sarah Palin.

But under the small-government, fiscal-responsibility rhetoric, a near-civil war has raged among Republicans over party direction, with some key exclusions at CPAC -- notably New Jersey's popular Governor Chris Christie and Virginia Governor Bob McDonnell -- highlighting the rift in the American right.

"To win, you have to have a big tent, and right now, we're shutting people out," said Howard Wooldridge, a retired police officer who has attended CPAC for the last seven years.

He criticized the lack of attention paid to draw African Americans, Hispanics and women into the fold.

"We're never going to win a presidential campaign until the Republican Party has a big tent, for all groups, and at least tries to relate to all Americans," Wooldridge told AFP.

President Barack Obama swept the minority vote last year, leaving Romney's Republicans flat-footed as they lost the White House as well as seats in the Senate and House of Representatives.

Some high-profile flameouts included two Senate candidates whose deeply controversial comments about women and rape contributed to their election defeats.

The 2012 losses triggered a GOP family feud, with some conservatives intent on jettisoning Republicans like Christie when they break with party orthodoxy, such as its stand on taxes or abortion.

Others, like Wooldridge, express concern that the demand for ideological purity will only marginalize Republicans at the ballot box.

For some party luminaries at CPAC, the advice was simple: halt the squabbling, which only turns off non-Republicans, including the all-important independent voters.

"We've got to stop this circular firing squad and recognize that we all need each other if we are going to have a chance of winning a presidential election again," warned Whit Ayres, a longtime political consultant and Republican pollster.

"The opposition is not fellow Republicans," he said. "The opposition is the American left and what they're doing to this country."

And yet some Republican lawmakers spoke openly about the divisions.

"The GOP of old has grown stale and moss-covered," Tea Party-backed Senator Rand Paul told the CPAC crowd.

"The new GOP, the GOP that will win again, will need to embrace liberty in both the economic and personal sphere," said Paul, whose profile has surged since he led a 13-hour legislative blocking tactic on the Senate floor last week to protest the White House's policy on unmanned drones.

"We must have a message that is broad," he went on, citing the need to appeal to "millions of Americans, young and old, native and immigrant, black, white and brown."

Rubio, a potential 2016 rival, could draw huge support from minorities. He is a charismatic Cuban-American leading the charge on what may be the most important immigration legislation in a generation.

The young senator from Florida said he knew liberals would savage him for not offering new ideas at CPAC, but insisted there was nothing broken with the Republican message.

"We don't need a new idea. There is an idea, the idea is called America, and it still works," he said to extended applause.

Texas Governor Rick Perry, who lost to Romney in last year's Republican primary race, brought his swagger to CPAC and insisted conservative values were not to blame for the party's recent failures, noting that might have been true "if Republicans had actually nominated conservative candidates in 2008 and 2012."

But he may have inadvertently highlighted the challenges of Republican outreach, when his complaint that "now we are told our party must shift appeal to the growing Hispanic demographic" elicited several boos.

They applauded, however, after he said an economic message, and not immigration reform, could win over Hispanic voters.