On Breitbart News Sunday, Rep. Jim Bridenstine (R-OK) announced he is endorsing Sen. Ted Cruz (R-TX) for president because Cruz’s principled conservatism, fundraising prowess, and discipline make him the best Republican candidate to take on and defeat Hillary Clinton.

Elaborating on his exclusive Breitbart News piece explaining his endorsement, Bridenstine told host and Breitbart News Executive Chairman Stephen K. Bannon on Sirius XM Patriot channel 125 that since he arrived in Washington in 2013, he has “seen how the D.C. incentives really challenge those of us who get to Washington, D.C. wanting to do the right thing.” He said there are “lobbyists who fund our campaign” and the “the political apparatus that wants to make sure we’re in line with the leader of the party.” The D.C. “incentive structure is so overwhelmingly powerful” that lawmakers “do things that we would never expect” and “vote for things we would have never expected them to vote for based on how they campaigned,” according to Bridenstine.

But he said that Cruz, who arrived in D.C. at the same time as Bridenstine, actually became more conservative and principled in Washington in an era in which so many politicians get elected by promising to change Washington only to let Washington change them and their values. And that is why conservatives can be assured that Cruz will not waver or cave if elected to the White House.

“Nobody comes to Washington, D.C. and becomes more conservative,” Bridenstine marveled when discussing Cruz. “Nobody comes to Washington, D.C. and becomes more principled.”

Bridenstine, who is one of the conservative movement’s rising stars, said that when deciding which candidate to back for president, voters should look for someone “who has shown up, faced the giants, looked at them face to face, rejected them, and in many cases defeated them.”

“There’s one person that’s running for president that I’ve seen inside the beltway stand up to the Washington establishment over and over again, and it’s not because he’s politically calculating… It’s because he’s very principled and he’s unwilling to waver on what he promised to the American people he would do when he got to Washington, D.C., and that is Senator Ted Cruz,” Bridenstine said. “We need a full-spectrum conservative that has proven he or she can fundraise, who has proven inside the beltway that they can look at the giants, face them down and defeat them, and I think the person that matches that description better than anybody I’ve seen is Senator Ted Cruz.”

Bridenstine described Cruz’s battle with the D.C. political establishment on gun control, immigration, and Obamacare to remind listeners of Cruz’s principled conservatism and accountability to voters.

The Oklahoma Congressman recalled that when he and Cruz first arrived in D.C. over two years ago, Republican leaders believed the party had to “change our approach to the Second Amendment” after the Sandy Hook massacre. The establishment GOP leaders felt Republicans should support universal background checks, a ban on so-called “assault weapons,” and limits to magazine sizes. He said while establishment Republicans were moving in this direction, “Cruz stood up behind closed doors and said this is not going to work. This is not what our constituents want.” Bridenstine reminded listeners that Cruz ” fought back hard against the media, against all of the D.C. graybeards,” and led the charge against more gun control by going “directly to the people.”

On border security, Cruz fought Republican leaders who believed the GOP needed to pass comprehensive immigration reform with either a path to citizenship or legalization, which Bridenstine said was “amnesty” since it rewards those who violated the laws to come into the country.

On Obamacare, Bridenstine said that Cruz, who pushed to defund Obamacare, was prescient in realizing that “once the subsidies begin flowing, you will never get it repealed, and the Supreme Court will never reverse it. Once you create the constituency of dependency, it will never get stopped.”

“We had to make sure it didn’t go forward,” Bridenstine said of Obamacare. “Ted Cruz was out in front making that case to the American people and he was making it to us in Congress.” He said though Obamacare eventually got funded, Cruz was proven right by June’s Supreme Court decision.

Bridenstine said that when the D.C. beltway establishment is going in one direction and “all of the ‘smart’ people say we have to do one thing,” Cruz “knows what the people back home are feeling and does the opposite–and he comes out on top.”

“He doesn’t do it by convincing the intellectual elite in Washington,” Bridenstine said. “He does it by speaking directly to the American people, and that is exactly what Ronald Reagan did.”

Bridenstine also said that Cruz’s discipline sets him apart from the other candidates, including Donald Trump, whom Cruz has praised for speaking out forcefully against illegal immigration. Bridenstine said Trump is “bringing very important issues to the table” and he’s “lead-tackling for the issues we need to talk about.” But the Congressman said that he was caught off guard by Trump’s comments regarding Sen. John McCain’s (R-AZ) service this weekend in Iowa. Bridenstine said though McCain “is not my favorite Senator,” he “has served his country valiantly” even though they “disagree on some very critical issues.”

“We cannot go into a general election against Hillary Clinton with someone who is not disciplined,” Bridenstine said.

A principled conservative like Cruz usually has trouble raising enough money to go the distance, but Bridenstine emphasized that Cruz’s proven fundraising ability is what makes him different–and much more viable–than conservatives who have run for president before.

“Ted Cruz is a proven fundraiser, and that will be necessary to defeat the Clinton machine. True grassroots candidates, like Ted Cruz, generally struggle after the first few primary states due to funding,” Bridenstine wrote in his Breitbart News piece. “Ted is different. He will go the distance. This alone should excite and motivate all of us who have been waiting for a full spectrum, grass-roots candidate to vie for the Republican nomination.”

Bridenstine said “this is our opportunity” to elect a true conservative president and, “it’s up to us to stand up and support him.”