In the Matheson ad, the empty seat with the word "vacant" written on the chair is used to show Philpot's early departure from serving as the representative for House District 45.
Matheson defended the ad, calling it a "factual representation" of Philpot. He also rejected claims it was an attack ad.
"I think this is aboveboard," Matheson said. "This is very factually based. I don't have eerie music or a sinister voice talking. But I've always run aggressive campaigns."
Philpot said the ad is a sign of the campaign's desperation and implied during public comments Monday at the state Capitol that his campaign has internal polling data showing a tight race.
"My opponent seems to have finally realized his political career is on its last legs," Philpot said. "This can be the only explanation for his most recent deceptive and negative campaign ads. He is showing his true colors namely that he will do anything to get re-elected."
The Philpot campaign wouldn't disclose its internal polling numbers, but the most recent public poll by KSL/Deseret News showed Matheson with a comfortable 26-point lead.
Dan Levin, associate professor of political science at the University of Utah, said the latest ad by Matheson is a way for the incumbent to put doubt in voters' minds about the authority of Philpot's campaign, which largely has been linking Matheson to unpopular House Speaker Nancy Pelosi and the general anti-incumbent mood of the electorate.
Levin also said it appeared the Matheson campaign had grown weary of taking shots by the Philpot campaign.
Philpot sought to address the assertions in the ad Monday and bristled at the claim that he took years to pay delinquent taxes.
"Because of our move to Michigan for law school, we did not receive notice of a tax liability before it went to court," Philpot said. "As soon as we did receive the tax notice, we paid the balance of $168.28 in full."
As for the missed votes in the state Legislature, Philpot said since the Matheson claim wasn't sourced, it was "hard for me to address the criticism directly." However, he did say he had one of the best voting percentages during his time in the Capitol.
But Matheson said his campaign went to the website for the Legislature and hand-counted the number of times Philpot was absent and it got the unpaid taxes data from court records.
The two traded barbs at a debate hosted on KUER/90.1 FM radio earlier in the day, where both attempted to paint sharp differences between their policies namely how Matheson would like to keep some aspects of the Obama-driven health care bill that passed and toss out other parts while Philpot would like to repeal all of it.
Both are scheduled for another debate on Sunday.
A new ad from Rep. Jim Matheson's campaign goes on the offensive against challenger Morgan Philpot. The negative tone of the ad is unusual for an incumbent who polls indicate has a comfortable lead. The campaign spot slams Philpot for missing votes, being late on paying taxes and taking state-paid health benefits after he left his state legislative seat.