The race to fill the lone Montana House seat vacated by Rep. Ryan Zinke, who was named interior secretary, just got a lot more interesting.

Already considered too close to call by both sides, GOP candidate Gianforte was involved in an altercation with a reporter for the ultra-liberal Guardian newspaper, where eyewitnesses say the tech millionaire body-slammed the journalist and began to punch him.

Fox News employees witnessed the attack:

As part of our preparation for a story about Thursday's special election to air on "Special Report with Bret Baier," we arranged interviews with the top two candidates, Republican Greg Gianforte and Democrat Rob Quist. On Wednesday, I joined field producer Faith Mangan and photographer Keith Railey in Bozeman for our scheduled interview with Gianforte, which was to take place at the Gianforte for Congress Bozeman Headquarters.

Faith, Keith and I arrived early to set up for the interview in a room adjacent to another room where a volunteer BBQ was to take place. As the time for the interview neared, Gianforte came into the room. We exchanged pleasantries and made small talk about restaurants and Bozeman.

During that conversation, another man – who we now know is Ben Jacobs of The Guardian – walked into the room with a voice recorder, put it up to Gianforte's face and began asking if he had a response to the newly released Congressional Budget Office report on the American Health Care Act. Gianforte told him he would get to him later. Jacobs persisted with his question. Gianforte told him to talk to his press guy, Shane Scanlon.

At that point, Gianforte grabbed Jacobs by the neck with both hands and slammed him into the ground behind him. Faith, Keith and I watched in disbelief as Gianforte then began punching the reporter. As Gianforte moved on top of Jacobs, he began yelling something to the effect of, "I'm sick and tired of this!"

Jacobs scrambled to his knees and said something about his glasses being broken. He asked Faith, Keith and myself for our names. In shock, we did not answer. Jacobs then said he wanted the police called and went to leave. Gianforte looked at the three of us and repeatedly apologized. At that point, I told him and Scanlon, who was now present, that we needed a moment. The men then left.

There's no doubt the Guardian reporter was being obnoxious and violated journalistic ethics by trying to horn in on an interview scheduled by another media outlet.  "Getting the story" does not include trying to prevent other journalists from doing their jobs.

But Gianforte had absolutely no call to attack Jacobs, no matter how obnoxious his behavior or arrogant his demeanor.  In a civil society, it simply can't be tolerated.

Will Gianforte suffer politically for the attack?

A few years ago, it would have ended his campaign.  But this is the age of Trump, where voters tend to look at the faults and foibles of candidates in an entirely different light.  There may even be some Montana voters who approve of Gianforte's assault on a liberal reporter. 

Several Montana newspapers have withdrawn their endorsement of Gianforte.  But since any newspaper endorsement is virtually ignored by the voters, it hardly matters. 

Two years ago, I would have confidently predicted the demise of Gianforte's campaign.  But today...who knows?  The Republican's problem is that even if it costs him only a few votes, in a close race, that may be decisive.  I think it's safe to say Gianforte didn't do himself any favors with his body-slamming a liberal journalist.