Sen. Ted Cruz pauses while addressing his supporters at the Grand Wayne Convention Center on April 28 in Fort Wayne, Ind. (Ricky Carioti/The Washington Post)

BURLINGAME, Calif. — Sen. Ted Cruz picked up an endorsement from former California governor Pete Wilson during the state Republican party convention here Saturday, bringing a deeply entrenched GOP establishment figure into Cruz’s fold even as his presidential aspirations appear to stall.

“The most urgent threat facing our next president will be the dangerous national security legacy of the Obama administration,” Wilson said in Burlingame, where Republicans gathered this weekend for the state Republican convention. “Ted Cruz does not need any tutoring on the clear and present dangers to America’s national security.”

The endorsement from the moderate former governor — who was blasted by the left during his tenure in the 1990s for his position on illegal immigration — showcases the extent to which senior members of the GOP leadership remain opposed to a potential Trump nomination. Many in the party worry that Trump’s bombastic rhetoric will hurt the party’s chances in November, while others — and Cruz in particular — remain skeptical of Trump’s conservative bona fides.

Wilson homed in on Trump’s weaknesses during his speech Saturday, referring indirectly to Trump as a “wild card” and questioning the type of Supreme Court justices the billionaire would appoint to the court as president. Perhaps most urgently, Wilson raised concerns about the impact that Trump could have on down-ticket races around the country that could decide control of the U.S. Senate.

“Friends, we cannot afford a Republican nominee that brings us down-ticket decimation of our 2014 hard-won midterm gains,” Wilson said. “We can’t afford a nominee in 2016 who is losing women voters at a far greater rate even than Hillary Clinton is losing men and millennial.”

“He is not anti-immigrant. He, as am I, is for the kind of legal immigration that has made this country great. And I might point out that he is hardly anti-Latino,” Wilson quipped.

The endorsement is not without irony for Cruz, whose career has rested on his anti-establishment message and his calls for conservative purity.

“I am honored to have the support of Governor Wilson, a solid Republican leader whose lifetime of public service demonstrates how Republicans focused on providing solutions to the challenges facing the American people can win in blue states as well as red,” Cruz said in a statement.

But Cruz’s presidential prospects have reached an apparent impasse amid a recent sweep of primary victories by Donald Trump, and his only hopes of securing the GOP nomination rest on winning the upcoming Indiana primary and doing well in a string of primaries on June 7. On Friday, Cruz also received the endorsement of Indiana Gov. Mike Pence (R).

California, which allocates the bulk of its delegates on a district-by-district basis, could represent Cruz’s last stand to chip away at Trump’s enormous delegate lead and force a brokered convention.

"California is at a crossroads. California is going to decide this Republican primary," Cruz said Saturday while addressing the convention. "It is going to be a battle on the ground district by district by district."

The Trump campaign, meanwhile, is bullish about its chances to win the nomination outright. The campaign has set its sights on strong showings in California and other June 7 states, which they hope will secure him enough delegates to win the nomination before the national convention in July.