BISMARCK, N.D. (AP) — North Dakota Rep. Kevin Cramer officially launched his campaign Friday night for U.S. Senate, giving Republicans the candidate many consider the best hope of unseating Democratic Sen. Heidi Heitkamp.

Cramer's formal announcement amid party faithful comes about a month after he first passed up the Senate race and said he would run for another House term instead, citing family considerations and his House seniority.

Cramer is a staunch advocate of President Donald Trump. Tom Campbell, a second-term state senator and the only other declared GOP candidate, trailed Heitkamp badly in name recognition and money, and had drawn little enthusiasm from the GOP.

Cramer told The Associated Press that Trump had personally encouraged him three times to run for the seat, including twice after he said he wouldn't.

"The president called and said, 'You have to stop thinking about yourself and start thinking about your country,'" Cramer told the AP before his Friday night announcement.

Republicans hold a 51-49 Senate majority. Heitkamp is among 10 Democrats in states Trump carried who are up for re-election in 2018.

The former state attorney general and gas company executive narrowly won her first term in 2012 in the heavily conservative state.