Former Montana state Sen. Ryan Zinke (R) won his party's nomination for the state's lone U.S. House seat Tuesday, beating his four opponents in what turned out to be a bitter race.

Zinke ended up getting 33 percent of the vote, with former state Sen. Corey Stapleton (R) and state Sen. Matt Rosendale (R) each getting 29 percent of the vote.

"I'm grateful to the tremendous showing of support from the people of Montana," said Zinke in a statement after his victory. "Now it's time to unite together, not only as a party but as Montanans committed to solving our nation’s problems and getting our economy back on track. I look forward to continuing to share my positive message, and joining you again in victory this November."

Zinke is a former Navy SEAL who created an anti-Obama super PAC in 2012. Although Zinke formally cut ties with the group shortly before his run for Congress -- as he was required to do legally -- the group became a source of controversy in the race because it aggressively touted its founder's candidacy and ran ads in support of him.

Republicans in the state even worried that that the arrangement could hurt Zinke in the general election.

In April, former GOP gubernatorial candidate Ken Miller wrote, "While [Zinke] claims no coordination between the groups, both conservatives and liberals alike are taken aback by this shady affiliation. This issue is already being brought up amongst liberals. ... These concerns are real and will be used to defeat Zinke in the general election, essentially give away the congressional seat."

Zinke also had to defend himself against prominent Republicans in the state who questioned his conservative credentials. At a recent debate, Zinke seemed to play to a conservative audience when he said he would back impeaching President Barack Obama.

In January, Zinke attracted attention for calling former Secretary of State Hillary Clinton the "anti-Christ" -- a remark he later said he regretted.