President Trump is speaking at a rally in Missoula, Mont., to tout support for Republican state Auditor Matt Rosendale, who is facing off against incumbent Democratic Sen. Jon Tester in a tight race for his Senate seat.

Trump won Montana’s 3 electoral votes by 20 points in the 2016 elections, and Rosendale’s campaign has focused on an unyielding support for the president. Tester, however, has held his seat for two terms since 2007.

Tester, who is the ranking member on the Senate Veterans’ Affairs Committee, was a strong voice in opposing the nomination of Trump’s White House doctor Adm. Ronny Jackson to head the Department of Veterans Affairs. Trump on Wednesday referred to the opposition on Twitter, stating that the Democrat made "vicious and totally false statements" about Jackson, and “behaved worse than the Democrat Mob did with Justice K!”