PHOTO GALLERY: President Trump campaigns in Billings

President Donald Trump waves to the crowd after doing a television interview before the start of a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump is interviewed before the start of a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

People respond as President Donald Trump arrives to speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

People respond as President Donald Trump arrives to speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump arrives to speak at a rally at Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Susan Walsh)

President Donald Trump arrives to speak at a rally at Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Susan Walsh)

President Donald Trump speaks at a rally at Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Susan Walsh)

People cheer as President Donald Trump arrives to speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump waves as he walks off of Air Force One at Billings Logan International Airport in Billings, Mont., Thursday, Sept. 6, 2018, with Sen. Steve Daines, R-Mont., second from right, and Rep Greg Gianforte, R-Mont. Trump is in Montana for a rally. (AP Photo/Susan Walsh)

People cheer as President Donald Trump arrives to speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump waves before getting into his car after arriving at Billings Logan International Airport in Billings, Mont., Thursday, Sept. 6, 2018. Trump is in Montana for a rally. (AP Photo/Susan Walsh)

White House Chief of Staff John Kelly pauses during a prayer before the start of a rally with President Donald Trump in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

People wait for President Donald Trump to arrive and speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump arrives to speaks at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump, center, shakes hands with Montana Attorney General Tim Fox, left, after arriving at Billings Logan International Airport in Billings, Mont., Thursday, Sept. 6, 2018. Trump is in Montana for a rally. (AP Photo/Susan Walsh)

President Donald Trump arrives to speak at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

White House Chief of Staff John Kelly walks down the steps of Air Force One at Billings Logan International Airport in Billings, Mont., Thursday, Sept. 6, 2018. He is traveling with President Donald Trump for a rally. (AP Photo/Susan Walsh)

President Donald Trump, third from right, walks off of Air Force One at Billings Logan International Airport in Billings, Mont., Thursday, Sept. 6, 2018, with Sen. Steve Daines, R-Mont., second from right, and Rep Greg Gianforte, R-Mont. Trump is in Montana for a rally. (AP Photo/Susan Walsh)

President Donald Trump speaks at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump finishes his speech at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump gestures to the crowd as he finishes his speech at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump points to people in the crowd as he finishes his speech at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump reacts to the crowd as he finishes his speech at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump waves to the crowd as he leaves the stage after speaking at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump reacts to the crowd as he finishes his speech at a rally in Billings, Mont., Thursday, Sept. 6, 2018.(AP Photo/Susan Walsh)

President Donald Trump speaks at a rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Jim Urquhart)

President Donald Trump speaks at a rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Jim Urquhart)

Republican Senate candidate Matt Rosendale, left, and President Donald Trump speak at a rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. President Trump used the stop to show support for Rosendale. (AP Photo/Jim Urquhart)

President Donald Trump finishes a television interview before speaking at a rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Jim Urquhart)

Supporters of President Donald Trump wait for him to speak at rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Jim Urquhart)

Attendees recite the Pledge of Allegiance before President Donald Trump speaks at a rally at the Rimrock Auto Arena in Billings, Mont., Thursday, Sept. 6, 2018. (AP Photo/Jim Urquhart)