PHOENIX – President Donald Trump's barrage of attacks on the late Sen. John McCain over the past week landed with a thud in many quarters.

But political experts expect Trump to keep heaping abuse on the legacy of his foil, a six-term Arizona Republican, into 2020.

With Arizona expected to be among a handful of states that could swing the presidential election next year and Trump's penchant for grievance-driven politics, McCain and his home state could play an outsize role in the national conversation over the next 18 months.

"Sadly, there is no chance that this is going to go away," said Rachel Bitecofer, a professor of political science who specializes in campaigns and polarization at Christopher Newport University in Virginia.

Trump will likely spend time during the 2020 presidential campaign in Arizona talking about his long-promised border wall, and he has ignored pleas from Republicans in the past to not discuss his views on McCain, she said.

"He gets into those rallies and he just can't help himself," Bitecofer said.

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Trump and McCain publicly battled from 2015 until McCain's death from brain cancer on Aug. 25, 2018. Seven months later, Trump is keeping the feud going amid the conclusion of an investigation by special counsel Robert Mueller, whose inquiry into Russian interference in the 2016 presidential election was fueled in part by a salacious dossier McCain gave to the FBI and a McCain associate distributed to the media.

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Trump in the past week has lashed out at McCain, blaming him for peddling the dossier he said was the work of Democrats, sinking Trump's health care plans by refusing to help roll back the Affordable Care Act and saying he wasn't thanked for approvingMcCain's funeral services in Washington.

Some are wondering how the attention on McCain may shape the legacy of the former prisoner of war and 2008 presidential nominee.

Rick Davis, McCain's presidential campaign manager and member of his inner circle, said McCain probably would have welcomed the continued attention.

"I'm sure there is a wry smile on John's face today knowing he's as relevant now as he was when he was still with us," Davis said. "I wouldn't expect it will be any different in the future. John McCain cast a wide shadow on Earth and now from heaven."

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Josh Scacco, a communications professor at the University of South Florida who specializes in politics, said that years from now McCain may be most known for having stood as a conservative bulwark against Trump. For now, though, Trump sees McCain as a villain who enabled his political enemies, Scacco said.

"The reason he's doing this is because John McCain is a central character in the Russia story," Scacco said.

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"For Donald Trump to build a metaphorical wall around himself, he needs to systematically attack the credibility of every actor in that story, whether it is Mueller, whether it is (Deputy Attorney General Rod) Rosenstein or whether it is John McCain delivering the dossier."

It also helps Trump steer the political conversation – and media headlines – where he wants them, Scacco said.

Others, such as Chris Herring, former chairman of the Maricopa County Republicans, counter that the latest saga in the Trump-McCain feud is overblown.

"I don’t know that a few days of comments is going to change" McCain's legacy, he said. "There’s people in Arizona that loved Sen. McCain. There’s people in Arizona that didn’t like Sen. McCain. I don’t think anyone is going to have their views changed by President Donald Trump."

When it comes to McCain, Herring said, "people’s opinions are entrenched. If anything, I think, over time, the people that didn’t like him, they would soften over time."

Robert Graham, former chair of the Arizona Republican Party, reminds people that McCain could be combative, too.

"Through his entire career, he’s basically had people that just don’t like him," Graham said. "The public – in Arizona and the whole nation – are familiar with people bashing on John McCain. Quite honestly, he always leaned in to a fight. ... I just don’t think any rhetoric, any discussion, is going to harm his legacy whatsoever."

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Trump's fixation with McCain creates more discomfort for U.S. Sen. Martha McSally, R-Ariz., who faces voters again in 2020, many political observers agree. Trump and McSally will top the GOP ballot in Arizona next year.

Trump's attacks on McCain could hurt McSally

McSally holds the Senate seat McCain held from 1987 to 2018 and, like him, draws on her experience as a combat pilot to define her public identity.

It's why she seems caught in the middle when Trump, who is wildly popular among Republicans, attacks McCain, who remains popular with a sizable slice of Arizona voters.

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"Politically speaking, there's no bigger loser than Martha McSally," Bitecofer said. "She is absolutely one of the most-endangered Republican incumbents. It's complicating for her because she can't really distance herself from the president without isolating Republican voters.

"At the same time, without defending John McCain, she's isolating the other half, those Republicans in that state who are deeply loyal to the McCains. And of course, it does not go over well with independents."

For her part, McSally encouraged Trump to lay off McCain in a phone call Wednesday.

It was an act of defiance for McSally, who welcomed Trump's support at Luke Air Force Base during her 2018 Senate campaign. On Thursday, at the same location, she created at least some distance from the president because of McCain.

"I made it clear I love John McCain. John McCain is an American hero," McSally told reporters gathered at Luke. "This state reveres John McCain, and his family deserves respect by everybody. And so that's my message."

The GOP is Trump's party, not McCain's now

Graham said it was amazing that McCain remained central to current events seven months after his death.

"That’s a remarkable legacy. The guy is not even alive and he still has a lasting impact on our country," Graham said. "Again, some would say for good, some would say for worse. But candidly, he kept getting re-elected, so that tells you what the people wanted."

The same could be said for Trump, at least among Republicans.

There is, at least so far, little political downside for Trump among GOP voters when he lashes out at former Republican luminaries such as McCain or former President George W. Bush.

"This is Donald Trump's Republican Party now," Scacco said. "Even openly defending John McCain is considered politically risky."

Reach the reporters at ronald.hansen@arizonarepublic.com or yvonne.wingett@arizonarepublic.com. Follow them on Twitter @ronaldjhansen and @yvonnewingett.