Bush endorsement signals establishment's move toward Cruz

Jeb Bush's endorsement of Texas Sen. Ted Cruz Wednesday morning signaled a growing inclination in the oft-touted Republican establishment: that even Cruz would be better for the party than Donald Trump.

Leaders in the GOP have long and openly mused that neither of the primary frontrunners fits the bill of an ideal Republican presidential candidate, but the race has failed to yield any alternatives.

"It's a signal that there's only a plan A and a plan B," said Mark Jones, a political scientist at Rice University's Baker Institute. "There is no plan C."

Some Republican pundits and officials had floated the notion of introducing a new candidate at the party's July convention, but the decision of a big Republican name like Bush to back Cruz suggests that the party won't be able to unify behind a newcomer.

RELATED: Analysis: Republicans forced to choose between Cruz, Trump

"For a long time [Republican leadership] was having difficulty deciding who get behind," said Cal Jillson, a political scientist at Southern Methodist University. "I think the establishment is beginning to make its choice in favor of Cruz."

On Tuesday night, Trump slightly expanded his wide lead in the primary race, and the possibility that Cruz could win the race outright faded further. Experts questioned what difference the Bush endorsement would make.

"It's good for Cruz, but probably about three weeks too late," said Brandon Rottinghaus, a political scientist at the University of Houston. "Trump has got such a lead and such momentum that it's hard to see that this could be a major force."

Rottinghaus wondered if the timing of the endorsement was planned to help Cruz edge Trump out of prominence in the news media Wednesday, but diverting attention from the mogul's big Arizona win towards Bush's comments, which have long been awaited.

RELATED: Arizona goes for Trump, Clinton

Bush is unlikely to move many voters towards Cruz — Bush himself never broke single digits in state voted before he abandoned his presidential bid — but he'll likely keep the money flowing. The Bush campaign sported the most potent network of high-dollar donors in the GOP field, and many of those backers have been waiting for the former candidates lead before giving again to another campaign, Rottinghaus said.

"This gives Cruz more of a rosy glow among the elite crowd," Rottinghaus said.

Bush's blessing could likely give Cruz the added marginal voter support he needs to prevent Trump from an outright win before the party's convention. If that happens, 2,472 delegates will re-vote for a nominee of the convention floor in Cleveland.

RELATED: Growing chance of contested GOP convention puts added focus on delegates

Ahead of that likely scenario, the candidates are campaigning for delegate support at state and county convention nationwide, and posturing to court full slates of delegates at the convention.

In that laborious process, experts said, Bush and his well-funded family apparatus would come in handy.