Iowa state Sen. Brad Zaun will face Democratic Rep. Leonard Boswell in November after comfortably defeating six candidates in Tuesday’s GOP primary, including a well-funded opponent who was backed by some House Republicans.

With more than two-thirds of the Republican vote counted in the 3rd district, Zaun had 48 percent after dominating the vote in populous Polk County (Des Moines), his home base. He did less well in rural counties, but he will top the 35 percent vote threshold needed to avoid having a nominating convention select a nominee.

The result was a setback to Jim Gibbons, who received 25 percent. Gibbons, a former college wrestling coach, raised more than three times as much money as Zaun ($447,000 to $121,000 through mid-May) and was backed by GOP luminaries such as Minority Whip Eric Cantor (Va.) and former Speaker Dennis Hastert (Ill.).

Gibbons had qualified for the second of three levels in the National Republican Congressional Committee’s “Young Guns” candidate recruitment and training program.

Zaun has not yet qualified for any level of the program, though the NRCC will now pivot to help him in the general election.

Aviation consultant Dave Funk, a favorite of some teas party activists, finished third with 19 percent. Four lesser-known candidates split the remainder of the vote.

Some observers expected that no candidate would break 35 percent of the vote, given that there appeared to be no runaway frontrunner in a packed field.

Boswell, who was unopposed in the Democratic primary, is seeking an eighth term.