HOUSTON — (CNN) Texas Gov. Greg Abbott will endorse Wednesday one of his political disciples, Ted Cruz, giving the Lone State senator his highest-ranking political endorsement thus far in the presidential race.

Abbott will formally back Cruz at an event Wednesday at 1 p.m. in Houston, campaign officials said, just six days before what is expected to be a competitive race with Donald Trump in Texas. Although not unexpected, the nod from Abbott is the clearest sign yet that the Texas Republican establishment is backing their freshman senator in his presidential ambitions.

“After 8 years of relentless attacks on our values from this White House, it’s our duty as Texas conservatives to support a leader we can trust to restore our values and move this country forward,” Abbott said in a video message out Wednesday. “That’s why I’m supporting Ted Cruz for president.”

Abbott will also quickly become the most senior political leader to back Cruz’s bid. No other governor has endorsed him, nor has any senator — including the state’s senior senator, John Cornyn.

A year ago, who Abbott would endorse in the Republican race — if he would at all — was one of the hottest questions in Texas politics. But as the field winnowed and the other candidates with ties to Texas — former Gov. Rick Perry, former Florida Gov. Jeb Bush, Kentucky Sen. Rand Paul and ex-Hewlett-Packard CEO Carly Fiorina — dropped out, it became increasingly clear that Abbott would choose Cruz, the state’s rising political star.

Abbott and Cruz share a hardline position on the governor’s top national priority: strengthening the nation’s border and rooting out illegal immigration. But their connection is also personal: When Abbott was the state attorney general under Perry, Cruz was Abbott’s solicitor general, arguing cases on behalf of the state before the U.S. Supreme Court.

Cruz has repeatedly spoken glowingly of Abbott on the campaign trail, frequently recalling the charge that Abbott gave him — to find constitutional fights where the Texas Attorney General could get involved, and to wage them.

Abbott, along with dozens of state legislators and Texas Lt. Gov. Dan Patrick, is expected to be a top surrogate for Cruz in the closing days of the Texas primary. Struggling to convince observers that he can do as well in the southern states on March 1 as he once hoped to, Cruz’s team is raising the stakes for his performance back home, pointing to delegate-rich Texas as a place that can put him back on even footing in the delegate race with his rivals.

But the state is not seen as a lock: Trump has spoken of beating Cruz in Texas, and the super PAC backing Marco Rubio has invested $1.5 million in this state this week to try and embarrass Cruz by weakening him back at home.

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