U.S. Congressman Beto O’Rourke, D-El Paso, officially declared his candidacy on Friday for the U.S. Senate seat held by Republican Ted Cruz.

“We can wait until 2020 and hope that we are successful, or we can decide that we are going to take back this country and we are going to take back this state,” O’Rourke told supporters at a rally in El Paso. “2018 starts right here, right now.”

Jim Henson with the Texas Politics Project says it will be a long shot for any Democrat to win. He says Ted Cruz’s favorability numbers are now back on the rise after a brief drop last year following his failed bid for the White House.

“Ted Cruz goes into this race with high approval numbers, particularly among Republicans,” Henson said, “and looking like a pretty strong candidate in a Republican state.”

Texas Governor Greg Abbott endorsed Ted Cruz for re-election on Friday morning.

“Since Ted Cruz was elected to the U.S. Senate, he has done everything he said he’d do for Texans, and more,” Abbott said in a statement. “From opposing gun control legislation, leading the effort to increase border security, and now spearheading the charge to confirm a constitutionalist to fill the vacancy on the Supreme Court, Ted is a fighter who is getting things done for Texas. Voters overwhelmingly rejected Democrat policies in 2016, and I’m confident Texans will continue that streak in 2018.”

O’Rourke said Friday that he wants to break the Republican streak and become the first Texas Democrat to win a U.S. Senate seat in nearly three decades.

“We need a senator who is going to provide a check and a balance and who will fight when necessary against a president who wants to build walls,” O’Rourke said. “Are you with me? Because I’m with you.”

O’Rourke is the first contender to officially challenge Cruz’s seat. U.S. Congressman Joaquin Castro, D-San Antonio, has also hinted at a possible run.

Cruz’s term in the U.S. Senate is up in 2018.