In an interview with Politico Sunday, former Texas governor and Republican presidential candidate Rick Perry officially endorsed Texas Senator Ted Cruz—a man he once viewed as a political opponent.

The massively popular Texas governor briefly made a go at the presidency last summer, but dropped out in September following disappointing poll numbers and fundraising. But now he's throwing his significant political weight behind his fellow Texan. Seeing the race as having narrowed to a two-man contest, Perry told Politico he is backing Cruz because he's the truer conservative.

"Of those individuals who have a chance to win the Republican primary, at this juncture, from my perspective, Ted Cruz is by far the most consistent conservative in that crowd," said the former governor. "And that appears to be down to two people."

Touting Cruz as a fighter and a man of "principle," Perry expressed confidence in his ability to continue to push back against the "Washington establishment." He also said he was "satisfied" that Cruz will be ready to be commander-in-chief on "Day 1."

"He knows he’s going to surround himself with people who do have that experience, and I’m very satisfied that on Day 1, he will be ready to be commander-in-chief," said Perry. "Partly because of the time he’s going to spend in learning what he doesn’t know, but he’s also surrounding himself with people who are extraordinarily capable and wise.”

At one point in the exchange, Perry offered some thoughts about why former governors like himself have failed to gain traction in the presidential contest.

"Gov. Scott Walker, Bobby Jindal, Rick Perry, Jeb’s barely making an impact out there—those are very skilled, very successful, very experienced governors. But the electorate doesn’t want that," he said, adding. "That’s why we have elections, why we democratically select leaders."

Though the idea that Perry would back a fellow Texan might seem predictable, as Politico notes, their often less-than-friendly history made the endorsement "hardly a sure bet."

The two were on opposite sides of the 2012 Senate primary race, when Cruz ran successfully against Perry’s then-lieutenant governor, David Dewhurst, in a contest that launched Cruz on the national stage. In his farewell address before the Republican-dominated state legislature last year, Perry warned against those who would place “purity ahead of unity” — a frequent criticism of Cruz's style. And Perry was somewhat critical of Cruz’s role in shutting down the government in 2013 over a health care battle.

Along with Iowa Congressman Steve King, Perry will help Cruz campaign this week in Iowa, where the race between Donald Trump and Cruz remains tight.

Read the full interview here.