In a clear sign that Jeb Bush is going to be keeping the GOP base at arm's length in the coming presidential campaign, the former Florida governor turned down an invite to attend an immigration summit sponsored by Iowa congressman Steve King.

The Hill:

The Washington Post first reported on Wednesday that Bush had declined the invitation to the summit, which will feature a host of other potential GOP presidential contenders, including Gov. Chris Christie (N.J.), Sen. Ted Cruz (Texas), Gov. Rick Perry (Texas), former Arkansas Gov. Mike Huckabee, and Dr. Ben Carson.
 
The summit in the early-voting state is a rite of passage for many Republican candidates seeking to shore up their support among the conservative base. Bush’s absence could fuel attacks against the governor from some on the right who say he’s too moderate to make it through the Republican primaries.
 
Bush has said that a candidate has to be willing to “lose the primary to win the general" — a signal that he doesn’t intend to pander to base voters or bend from his centrist positions on immigration and Common Core education standards in 2016, even if it costs him support with grassroots conservatives.
 
Still, his absence will further highlights the rift on immigration between himself and others in the party who say he’s too soft on the issue.

King is among the most hawkish Republicans on Capitol Hill on the issue of immigration. He has stoked controversy in the past, most notably for saying that immigrants crossing the border have “calves the size of cantaloupes because they’re hauling 75 pounds of marijuana across the desert.”
 
King's often heated rhetoric is in stark contrast to Bush's, who has said many immigrants cross the border illegally out of an “act of love” to be reunited with their families.
 
In an interview with the Post, King wouldn’t speculate on why Bush had declined the invitation.
 
“I want all of the possible candidates to come to Iowa and make their pitch,” he said. “They should all come and speak to activists and interact with conservatives. I hope he finds a chance to do so.”

Bush is counting on the conservative vote being badly split so that no one candidate on the right can challenge him until he has built up a large delegate lead.  But Bush will have his own problems if Chris Christie enters the race.  The New Jersey governor will be pursuing the same voters as Bush, and a split in the moderate vote could be a boon to conservative candidates.

In the end, it will be a money game, and Bush has no equal in the fundraising department.  It's very possible that the 2016 GOP nomination fight will be the longest, the most expensive, and the most divisive ever seen.