LAS VEGAS — Sen. Dean Heller on Sunday endorsed Sen. Marco Rubio's White House bid, providing the Florida Republican with a boost heading into Tuesday's GOP presidential caucuses in Nevada.

Heller was an early backer of Jeb Bush. But the former Florida governor exited the race on Saturday after disappointing results in South Carolina and a presidential campaign that never really took off. Heller is Mormon and is based in northern Nevada, and his endorsement of Rubio, even two days before the caucuses here, could help the Floridian coalesce votes in what is essentially a three-way contest with frontrunner Donald Trump and Sen. Ted Cruz of Texas.

Heller announced the endorsement on Twitter. ".@marcorubio is the next generation of conservative leadership, and I am proud to offer my full support: #TeamMarco"

Nevada is a swing state that is ethnically diverse and has a signficant Hispanic voting bloc, and Heller has repeatedly aired his concerns — publicly — that a Trump nomination would doom the GOP ticket here in November. The Republicans are trying to flip the seat made vacant by Senate Minority Leader Harry Reid's retirement; House seats can also be competitive.

Heller isn't alone in worrying about Trump's impact on the GOP in Nevada. Gov. Brian Sandoval told the Washington Examiner in December that Trump's rise threatened gains the party has made in the state over the past few years.