“The people of Texas in all 254 counties are proving that when we reject PACs and come together not as Republicans or Democrats but as Texans and Americans, there’s no stopping us,” O’Rourke said in the statement. “This is a historic campaign of people: all people, all the time, everywhere, every single day — that’s how we’re going to win this election and do something incredible for Texas and our country at this critical moment.”

Cruz and O’Rourke have been embroiled in a surprisingly tight race for the Senate seat, with Cruz holding a 7-point edge, according to polls. The last Democrat to serve as a U.S. senator from Texas was Bob Krueger in 1993.