Texas Rep. Joaquin Castro announced to supporters that he won’t challenge Rep. Beto O’Rourke to be the Democratic nominee against Sen. Ted Cruz next year.

In an email to supporters, Castro explained his decision not to run explaining that Texans want a senator who would stand up to President Donald Trump.

“With the threats posed by Russia and North Korea, coupled with the reckless behavior of this administration and their failure to invest in economic opportunity for the American people, at this time I believe I can best continue that work by focusing on duties in the House Foreign Affairs and Intelligence Committees,” he said.

The decision would allow for the party to coalesce around O’Rourke, so far the only Democrat in the race.

Castro is said to be mainly focused on rebuilding the Texas Democratic Party and is likely aware of the damage a loss to Cruz would cause to his brand, reported the San Antonio Express News, which first reported Castro’s decision, citing Democratic sources.