Oz campaign dials up attacks on Fetterman after he rejects first Pa. Senate debate.

An already acerbic Pennsylvania Senate race got even more combative this week after Lt. Gov. John Fetterman said he won’t attend a debate that he and Republican opponent Mehmet Oz were invited to next week.

The debate, at the KDKA-TV station in Pittsburgh, was scheduled for next Tuesday. Fetterman’s campaign officially declined the invitation this Tuesday, unleashing a deluge of insults from Oz’s campaign, which has challenged him to five debates.

“We were just informed by ... KDKA that the Fetterman campaign is declining to attend the KDKA debate,” Brittany Yanick, an Oz spokesperson, said in a statement late Tuesday. “John Fetterman is a liar, a liberal, and a coward.”

The Oz campaign earlier in the day released a list, dripping with sarcasm, of concessions it would grant Fetterman regarding debates. “Doctor Oz promises not to intentionally hurt John’s feeling at any point,” the campaign said. “We will allow John to have all his notes in front of him along with an earpiece so he can have the answers given to him by his staff in real time. ... We will pay for any additional medical personnel he might need to have on standby.”

Fetterman responded with his own statement Tuesday night, shaming Oz for “mocking a stroke survivor.”

Political campaigns are rarely cordial affairs, particularly in a high-stakes Senate race in a state as closely divided as Pennsylvania. But this week’s escalation seemed to represent a breakdown of any kind of decorum, and to signal that neither campaign is taking the other seriously. And it illustrated a recent tonal shift from Oz’s campaign, which has increasingly attacked Fetterman’s health.

» READ MORE: Polls show Fetterman’s lead against Oz narrowing

Oz — who has trailed Fetterman by between five and 10 percentage points in most public polls and was hugely outspent on TV advertising over the summer— is eager to get his message out on live TV against Fetterman. Given his long history as a TV doctor, his campaign would expect him to perform well on a debate stage.

Fetterman, who was also criticized in the Democratic primary for avoiding debates, is not a strong debater and is also still recovering from a stroke that sidelined him from the campaign trail for months.

Fetterman said Tuesday that Oz’s campaign “made it abundantly clear that they think it is funny to mock a stroke survivor. I chose not to participate in this farce. Any sense that these ‘challenges’ were done in good faith is damaged. My recovery may be a joke to Dr. Oz and his team, but it’s real for me.”

He also acknowledged he continues to work on speech issues after his stroke.

“As I recover from this stroke and improve my auditory processing and speech, I look forward to continuing to meet with the people of Pennsylvania,” Fetterman said. “They’ll always know where I stand.”

And he said he would welcome a “productive discussion of how we can move forward” with Oz — without committing to any debate appearances.

» READ MORE: Fetterman keeps attacking Oz for being from New Jersey. That’s resonating in parochial Pa.

In campaign appearances, Fetterman has talked about his stroke as a way to push for better access to emergency health services in rural areas and to connect with voters by asking who has had experience with health challenges.

“Can you even imagine if you had a doctor mocking your illness, or ridiculing that?” Fetterman asked at a recent event in Western Pennsylvania, video of which the campaign circulated Wednesday. “Well, here we are. I would like to think that Dr. Oz may have really lost his way if you’re gonna make fun of somebody that had a stroke.”

Fetterman had a stroke May 13 and had a pacemaker and defibrillator implanted in his chest. He said in a statement weeks later that the stroke nearly killed him but that he was expected to make a full recovery. A note provided by the campaign from cardiologist Ramesh Chandra gave Fetterman a good prognosis, while also chiding him for not taking his health more seriously before.

“If he takes his medicine, eats healthy and exercises, he’ll be fine,” Chandra said. “If he does what I’ve told him … he should be able to campaign and serve in the U.S. Senate without a problem.”

His campaign has stressed that Fetterman is in good mental and physical health and that the lingering problems are solely related to auditory processing challenges.

» READ MORE: Mehmet Oz’s new hometown is a private, religious community where opinions on him are split

As Fetterman has ramped back up his appearances, some speech difficulties are apparent in the brief remarks he’s given. He often speaks haltingly or appears to be searching for a word, sometimes landing on the wrong one. He’s done very few interviews. As video of Fetterman’s speeches have circulated, the tone of the race has taken a notable shift. Oz’s campaign pivoted from attacking Fetterman’s absence from the trail to directly questioning Fetterman’s health.

In one case, Oz spokesperson Rachel Tripp suggested Fetterman might not have had a stroke if he “had ever eaten a vegetable in his life.” Oz, asked about the comment in a radio interview Tuesday, suggested his campaign spokespeople don’t necessarily speak for him, and wished Fetterman the best.

“John Fetterman should be allowed to recover fully,” said Oz, a cardiothoracic surgeon. “And I will support his ability, as someone who is going through a difficult time, to get ready.”

The next morning, his campaign sent out a list of the “Top 10 Reasons John Fetterman Pulled out of the KDKA-TV Debate.”

The lineup included “Might accidentally reveal a health condition that’s worse than previously disclosed!” and “Taking questions from reporters IN PERSON ... ICK!”