U.S. Sen. Rand Paul, R-Ky., speaks with people at the Peppermill restaurant Jan. 16 in Las Vegas. (John Locher/AP)

The Republican Party has long been riven between its establishment and conservative wings, a split that plays out every four years in the race for the White House.

But for 2016, the divide in the early race for the GOP nomination is as much generational as ideological — pitting familiar, entrenched party figures from past battles against a younger crowd of ambitious senators and governors whose politics have been forged during the Obama years.

Moves by business-friendly favorites Mitt Romney and Jeb Bush toward 2016 bids have only served to widen the gap, as has the return of conservative Mike Huckabee, who had been perched at Fox News since George W. Bush was in the Oval Office.

Calls for a new GOP order have intensified in part because the budding contenders know they need to act fast: By the time the primaries begin, Republicans traditionally rally around seasoned candidates. The competing hopefuls — from Sens. Rand Paul (Ky.) and Ted Cruz (Tex.) to Govs. Scott Walker (Wis.) and Chris Christie (N.J.) — believe they have a narrow window of time to make the case for an alternative.

The Democratic side also faces a fissure between old and new, as potential front-runner Hillary Rodham Clinton is criticized by Republicans and some Democrats as being rooted in her husband’s 1990s administration and out of step with the progressive winds swirling within her party.

Texas Gov. Rick Perry, right, and RNC Chairman Reince Preibus speak to fellow Republicans at the Republican National Committee's annual winter meeting Friday in Coronado, Calif. (Sandy Huffaker/Getty Images)

But the argument is especially stark among Republicans and contrasts with the usual political rift in the first lap of GOP presidential contests. Amid the scramble to win over donors and early-state activists, Republican candidates have historically aligned themselves either as representatives of the movement right or the most viable mainstream standard-bearers.

Many of the initial 2016 skirmishes have become fights between veterans and rookies, with few intense policy disagreements in a party that is largely in unison on its platform.

“It’s kind of the passing of the torch. We’ve got the younger guys coming up, but there’s an awful lot of guys who think they have and do have a lot of experience to offer the country,” Sen. John Thune (R-S.D.) told reporters this week at a GOP retreat in Hershey, Pa.

In New Hampshire on Wednesday, Paul, 52, issued a barbed response to the news of Romney’s interest in a possible 2016 campaign, telling the NH Journal Web site: “When you do the same thing and expect a different result, it’s sort of what Einstein said, that the definition of insanity is to do the same thing over and over again.”

And speaking in San Diego on Thursday to members of the Republican National Committee, Walker, 47, argued that it is imperative for Republicans to give voters a vivid contrast to a potential Clinton revival.

“If we’re going to be up against particularly Hillary Clinton, we need to offer a new, fresh approach,” Walker said.

Christie — whose top backers have been courted by Bush and Romney in recent days — has also shrugged off the flurry of activity by his party’s elders.

“What I’ve told everybody — supporters of mine, potential donors of mine, staff — is: ‘Relax,’ ” Christie, 52, told a New Jersey radio station Thursday. “No one’s voting for another twelve and a half months.”

The entry of Bush, 61, the son and brother of presidents and a former Florida governor, and Romney, 67, the party’s 2012 nominee and a former Massachusetts governor, has given Republicans eyeing a campaign additional considerations as they plot paths to power.

The surprising decision this month by Huckabee, a former Arkansas governor, to leave his television job has had a similar rippling effect, speeding up the calls and organizing by candidates who are competing for the same evangelical voters.

Former Pennsylvania senator Rick Santorum, who won 11 primaries and caucuses during his 2012 presidential campaign, is also ramping up for 2016, and will huddle with GOP mega donor Foster Friess and political operatives in Arizona this weekend.

John Brabender, Santorum’s strategist, said Santorum will make an unapologetic case for experience and bet that Republican voters will eventually coalesce around a previously tested political leader.

“That’s an area where Romney is correct. Running a second time is infinitely different than running the first time,” Brabender said. “You’re a vastly better candidate. The wild-card question is: Is there a point where you wear out your welcome?”

As many as four GOP presidential candidates who ran in 2008 or 2012 appear likely to get in: Romney, Huckabee, Santorum, and Gov. Rick Perry (Tex.), who underscored his message to national Republicans in a farewell speech to the Texas legislature Thursday.

Next week, Bush will be in Washington to meet with lobbyists and party officials as he moves forward with plans to expand the coffers of his political-action committees, days after he was in California and New York for fundraisers. Romney, who spoke to the RNC’s winter meeting Friday in San Diego, is calling his broad network of allies and asking them to sign up with his fledging 2016 endeavor.

Bush advisers say he should not be lumped together with Romney and Huckabee, citing his lack of previous presidential campaigns and his frequent engagement with Republican leaders and support for GOP candidates during Obama’s presidency.

“Jeb is new, and a lot of people are interested in finding out more,” said Doug Gross, an Iowa-based Bush supporter. “He has the benefit of a name that gets him attention right away, but people will see he’s not his dad or brother.”

Still, Paul, Cruz, and other tea-party conservatives who have stormed to prominence during the Obama presidency believe they have an innate feel for the pulse of the Republican Party’s base that is unmatched by their out-of-office brethren. They see an opening for a presidential candidate who can speak to the frustrations of GOP primary voters.

At a conservative gathering in Washington on Monday, Cruz said the “biggest divide in America is not between Republicans and Democrats, it’s between career politicians and the American people.”

Maryland neurosurgeon Ben Carson, a conservative favorite and another probable 2016 candidate, said in a Thursday luncheon address to the RNC, “I swear, I will never be a politician. It doesn’t matter what position the Lord chooses to put me in, I will not be a politician.”

In speeches this week, Christie, Walker and Ohio Gov. John Kasich cast themselves as rising voices for Republicans who could guide the party in the post-Obama era and best help the GOP to expand its reach into blue states.

“But there’s one thing that people in my political party don’t always understand. Economic growth is not an end unto itself,” Kasich said Monday in his inaugural remarks for his second term. “Economic growth provides the means whereby we can reach out and help those who live in the shadows.”

Walker said in a statehouse address in Madison on Tuesday that “government has grown too big and too intrusive in our lives and must be reined in, but the government that is left must work.”

Reince Priebus, the RNC chairman, said in an interview Thursday that he welcomes a diverse field with a range of ages and views. “Most people in this country are far more intrigued with what we’re doing than talking about the same-old, same-old, day-old bread, boring Democratic Party,” he said.

Democrats, meanwhile, are content to watch the unfolding Republican drama from afar as Clinton quietly staffs up for her expected campaign.

A national survey released Friday by Democracy Corps, a group founded by Democratic consultants James Carville and Stanley Greenberg, shows Clinton leading Romney 49 percent to 43 percent and ahead of Bush 52 percent to 40 percent among likely 2016 voters.

When asked at a news conference Friday about Romney’s possible run, President Obama answered with a half smile: “I have no comment.”

Philip Rucker and Dan Balz in San Diego and Paul Kane in Hershey, Pa., contributed to this report.