Mitt Romney campaigns with Jeb Bush, left, on Oct. 31, 2012. (Melina Mara/The Washington Post)

Conservative leaders this week shrugged off the sudden moves by Jeb Bush and Mitt Romney toward 2016 presidential campaigns, saying the two establishment-friendly candidates are too far out of touch with grass-roots activists to win the Republican nomination.

At the same time, potential candidates with close ties to the party’s conservative base have moved to speed up their own efforts in response.

Senior advisers to several of the potential conservative candidates said Wednesday that GOP insurgents will have to do more in 2016 than they did in previous cycles to make a serious run for the Republican nomination. Building a campaign nest egg and winning the support of mega-donors to fill the coffers of allied super PACs has become a particular priority.

Former senator Rick Santorum of Pennsylvania, a populist conservative who won 11 primaries and caucuses in his 2012 presidential campaign, called his top donors and advisers Wednesday to join him in Scottsdale, Ariz., this weekend to plan his likely 2016 bid.

Foster Friess, a wealthy conservative whose funds propelled Santorum’s last campaign, will host the gathering. Santorum associates said Friess would make a presentation about the need for the hard-charging former lawmaker to expand his financial operation.

Former Arkansas governor Mike Huckabee — who has also won the Iowa Republican caucuses — has been busy calling evangelical leaders and conservative donors and readying a tour to promote his soon-to-be-published book, “God, Guns, Grits, and Gravy.”

Other possible conservative candidates, such as Maryland neurosurgeon Ben Carson, Sens. Ted Cruz (Tex.) and Rand Paul (Ky.), and Govs. Scott Walker (Wis.), Bobby Jindal (La.) and Rick Perry (Tex.) are hiring staff, building their fundraising shops and scheduling visits to early-primary states — all with the intent of gaining early attention and organizational strength in a race that may demand both.

Carson and Walker are scheduled to speak Thursday at a Republican National Committee meeting in San Diego, while Perry will take the same stage Friday. Romney will address the officials Friday evening.

“Our goal is to fight [New Jersey Gov.] Chris Christie and Rand Paul and whoever the whole way,” said Terry Giles, Carson’s chief political aide. “We’re already installing ground forces and raising significant money so we can ride what we think will be an anti-establishment groundswell.”

Brent Bozell, head of the conservative group ForAmerica, said a Bush-Romney fight would be good for the party.

“I’m just going out to buy popcorn and watch,” he said. “It’s going to be the first time in a long time where you’ll see multiple candidates fighting over the moderate standard of the party, instead of only seeing the conservatives battle each other.”

Sarah Palin, the former 2008 vice-presidential nominee who campaigned for Romney in 2012, said Wednesday on “Inside Edition” that “we need new energy. We need new blood. We need new ideas.”

Steve Deace, a conservative radio host in Iowa, said the GOP base must eventually unite behind a single conservative candidate.

“Some conservatives think Romney is self-delusional, but that doesn’t mean we should sit back,” Deace said. “Are we going to split our vote again? It’s time for us to find someone and say, ‘This is our son with whom we are well pleased.’ ”

Not all on the right are ready to rule out backing Bush or Romney. Rep. Steve King ­(R-Iowa),­ an immigration hardliner, said Wednesday that he has invited Romney to speak later this month at a conservative gathering in Des Moines, and he urged activists to give the former nominee a fair hearing.

“He may not be able to come to our event because of scheduling conflicts, but he knows the door is open and we made sure we rang the doorbell,” King said.

A Romney representative did not respond Wednesday to an e-mail inquiry about King’s invitation.

Bush decided in December to bypass King’s event, citing his own scheduling issues. Bush is one of the rare Republican contenders to turn down King, who has sparked controversy for his comments about illegal immigrants. Cruz, Paul, Santorum and Christie, among many others, are planning to appear.

John Bolton, a hawkish former U.S. ambassador to the United Nations who is mulling a 2016 presidential campaign, said the moves by Bush and Romney would not have an impact on his deliberations.

“I’m not dissuaded by the heavy hitters and the wall of money,” Bolton said in an interview. “They are factors, sure, but they are not the only factors. This is going to be a very large field and we’re going to see some robust debates where your judgment on a whole range of issues will be tested.”

William Kristol, the editor of the Weekly Standard, said conservatives should not rush to embrace the prospect of a Bush-Romney brawl in the GOP primaries, and cautioned that history proves such scenarios can lead to unpredictable outcomes.

“Conservatives are telling themselves, ‘This is great.’ But if you go back to 1988, which I’m old enough to remember, they thought early on that Bob Dole and George H.W. Bush would knock each other out and open up room for Jack Kemp or [Pierre S.] du Pont, only to watch Bush and Dole storm ahead.”