Kamala Harris used a rally in Grand Rapids, Michigan, on Friday to seize on reports that Donald Trump had been canceling media interviews to question whether he has the stamina for a second presidency if voters choose him over her in November’s election.

“If he can’t handle the rigors of the campaign trail, is he fit to do the job?” the Democratic vice-president, 59, told rallygoers about the 78-year-old Trump.

She said: “Trump is unfit for office.”

Harris and her Republican opponent were in Michigan as the weekend began while trying to shore up support in a battleground state that could decide their 5 November race. Polling suggests Michigan as well as its fellow “blue wall” states of Pennsylvania and Wisconsin remain in play for both candidates as the campaign’s waning days arrive.

“This is the place that is going to decide the election, right here,” Democratic representative Hillary Scholten told Friday’s audience as she opened the event.

Among the crowd, some Harris supporters struck a hopeful tone. “It’s about time for a woman to lead,” said Jenifer Lake, who took her daughter Adeline Butts to the rally for a chance to “see history in the making”.

Butts, who will be old enough to vote for the first time this election, described herself as mostly concerned about the cost of living, tuition and housing affordability. Her fellow attendee Bill Bray, who came to the rally from Adrian, Michigan, said he believed Harris would better promote economic opportunity for those situated like him than Trump would.

Bray grew up “in a poor neighborhood” but said he is doing well thanks to benefits from his prior military service as well as his long career at Ford Motor Company. He said he wants other people to have a chance at that same trajectory.

“Trump doesn’t understand equality,” said Bray, a veteran of the Vietnam war who also accused the former president of dodging the military draft that would have sent him to the same conflict.

Bray also said he supports stronger federal gun control after seeing “what guns do to people” and has no faith in Trump – who is widely supported by the firearms industry – taking that issue seriously.

Other attendees said abortion access was at the top of their mind. Harris has campaigned on preserving abortion access while three of Trump’s appointees to the US supreme court helped eliminate federal abortion rights in 2022.

“It’d be nice to have control of my body back, and then I’ll think about listening to the other side,” Kim Osborn said.

Lauren Rockel said she would like to see Harris fight to reinstate the Roe v Wade protections that Trump’s supreme court appointees helped strip away.

“There are people dying” as a result of abortion restrictions that have since gone into effect in many states, Rockel said: “It’s awful.”

To them, Harris said it was “time to turn the page” on Trump.

Gretchen Whitmer, the Democratic governor of Michigan, spoke before Harris took the stage. Four other Democratic state governors joined her.

Her presence and that of the other governors “shows how important you are, Michigan”, Whitmer said. She told the crowd that they would be the ones to “take our country forward” if they helped send Harris to the White House.

Michigan’s Democratic US senator Debbie Stabenow also spoke before Harris, alluding to how it got “scarier and scarier” the more she thought about the proposed policies of Trump’s supporters. The former president has sought to distance himself from the far-right Heritage Foundation, whose Project 2025 plan calls for the mass firings of civil servants and exalts the idea of outlawing abortion altogether during a second Trump presidency.

But he has struggled to effectively do that, with Trump’s running mate, JD Vance, having written the foreword for a book by the Heritage Foundation’s president. And, echoing Stabenow, many attenders said they were fearful of what a return to the Oval Office for Trump may produce.

The Democratic nominee’s message resonated with Richard Bandstra, who described himself as a “former Republican”. Bandstra said he came to the rally to hear a message of hope – and, as he saw it, to fight for what he called the most important issue of the race: preserving American democracy.