Republican U.S. Senate hopeful Jon Keyser unveiled an ad Tuesday that highlights his history as a combat veteran and takes aim at Democratic incumbent Michael Bennet’s position on the nuclear deal with Iran.

“Military intelligence officer Jon Keyser conducted capture and kill missions to remove high value targets in urban areas,” says a narrator over footage showing Keyser’s uniform, dog tags and a Bronze Star he was awarded.

“We weren’t fighting amateurs; we were fighting a vicious enemy armed by Iran,” Keyser says, speaking into the camera. “Now Obama wants to give these guys nuclear weapons and Michael Bennet, he was all for it. For me, it’s personal. You don’t trust Iran and you can’t trust Michael Bennet.”

The major in the Air Force Reserve has focused his campaign around his assertion that Bennet’s support for the Iranian nuclear agreement endangers the world. The fact-checking organization PolitiFact, however, recently ruled as “false” a Florida Senate candidate’s similar claim that the deal “allows Iran to produce a nuclear weapon.”

A spokesman for Keyser, one of five Republicans on the primary ballot, declined to say how much the candidate is spending on the ad, although media trackers report the campaign is so far spending just $4,500 to run the spot on Fox News Channel, starting on Thursday.

Primary rival Robert Blaha was the first of the GOP Senate candidates to go on the air, spending more than $50,000 on an attention-getting ad depicting a man undergoing a rectal exam. Like another Blaha ad that started airing around the state two weeks ago, it featured the “Blaha Product Guarantee,” a promise that he won’t seek another term if he doesn’t fix the tax system, reduce the deficit and cut illegal immigration in half.

Blaha’s spokeswoman wouldn’t say how much the campaign is spending on the current ad, which depicts a crowd of bobble-heads and calls the candidate the “cure for congressional blahs.”

That’s in contrast to $450,000 primary rival Jack Graham has spent to air a biographical ad since last week on broadcast and cable networks in Colorado’s media markets. “I’m a businessman with a track record for getting things done,” Graham says in the 30-second ad.

A spokesman for Graham’s campaign said that figure covers two week’s worth of ad buys, through June 5, and that the campaign will stay on the air “at this heavy level” through the primary election.

Mail ballots go out to voters statewide next week and are due back June 28.

“Our buy dwarfs Blaha’s buy, and Keyser’s buy is an absolute joke designed only to get the media to write about his ad,” Graham campaign manager Dick Wadhams said on Tuesday.

A fourth candidate, Ryan Frazier, was taping an ad on Tuesday morning and plans to start airing it statewide next week, his campaign said. His initial television buy will be $100,000, campaign spokesman Roger Hudson told The Colorado Statesman, with “several” subsequent ad buys planned in the near future.

A spokesman for the Colorado Democratic Party greeted Keyser’s ad with disdain, referencing allegations that the nominating petitions that secured the Republican a place on the primary ballot contain forged signatures.

“Jon Keyser is the handpicked choice of D.C. Republicans creating gridlock in Washington, and already his claims have been dismantled by the nonpartisan fact checking organization PolitiFact, as well as The Denver Post,” said Chris Meagher. “Given that they are still enveloped in a fraud scandal, it seems apparent the Keyser campaign has some real problems with honesty.”

Bennet has been airing several ads – including one about beer production and another about proposed congressional reforms – in heavy rotation statewide since early April.

– ernest@coloradostatesman.com

This post has been updated to reflect that the Frazier campaign says its initial advertising buy is $100,000, not $20,000, as the campaign originally said.