Steve Isley sees no reason not to believe what Donald Trump has to say about Congress’s impeachment investigation.

“The Democrats have been trying to impeach him ever since he got elected, so I’m not too wild about it,” said the retired construction worker. “So far I’m doubtful they have any evidence.”

But even Isley, who is planning to vote for the president again next year and scorns all Democrats as “socialists”, is prepared to keep open the possibility that, as the first public hearings begin in Congress next week, the investigation might reveal wrongdoing by Trump that would make impeachment legitimate.

“It’d have to be something along the lines of Nixon,” he said of the president who resigned over Watergate. “It’s not bad enough at this point.”

Isley, who grew up on a Kansas farm, lives in Johnson county, a Kansas City suburb that flipped from supporting Trump in 2016 to unseat a Republican and elect Sharice Davids, a gay Native American, to Congress as a Democrat two years later.

The swing in votes reflected a shift away from Trump in suburbs across America that would appear to complicate his re-election in 2020 if he’s unable to bolster support elsewhere, particularly in rural areas of swing states.

The impeachment hearings unfolding in Washington, which will enter their public phase on Wednesday, look unlikely to help.

The Republican leadership’s efforts to whip up outrage against the process as illegitimate, including a stunt where members of Congress stormed a room where witness depositions were being taken to claim Democrats were trying the president in secret, has again riled a hard core of Trump supporters to rally angrily in his defense.

But there is also a part of the electorate that voted for him – less ideological Republican supporters and independents – who are prepared to see where the evidence leads. They have a more open mind than Trump campaign strategists would like.

A Fox News poll showed nearly half of Americans favor impeaching the president and one-third of those opposed could change their minds if presented with new evidence.

“I vote Republican or I don’t vote,” said Bill Harris, a business manager who supports Trump. “This is all political. Nancy Pelosi is out to get Trump. Anyone can see that. That’s Washington. But I do think he has questions to answer. We need to hear the evidence, hear the people who were there. I’m not against that.”

Harris said he knows of others who voted for Trump whose doubts about the president have been stacking up and that if there is evidence of wrongdoing it would turn them away from him.

“There are those who defend him no matter what and then there are those people who think he’s too unpredictable, too unstable. He’s done some good things on trade but I think there are a lot of Republicans like myself who have doubts and concerns. I wish he would keep his mouth shut,” he said.

Then he added an afterthought.

“It would be a mistake for the Democrats to remove him. They should let the election do that. If the Democrats have the evidence, the voters will make the decision,” he said.

That is precisely what some Johnson county Democrats are counting on. The county won’t make much difference to the overall outcome of the presidential election as Kansas is a solidly Republican state. But it will be crucial in Davids’ fight for re-election and maintaining Democratic control of Congress, and it is reflective of the shift in other big city suburbs across the midwest, which will have an important say in who wins in 2020.

Nancy Leiker, the chair of the Johnson county Democratic party, said impeachment is not the most important issue for most voters. That remains healthcare.

“But I can’t help but think that as the investigation goes on and becomes more public, those numbers will change,” she said.

Leiker said opposition to Trump has drawn more people into campaigning and Democrats think the impeachment hearings can only help.

Cassie Woolworth, a contract IT analyst and single mother of three boys, was among those who largely ignored politics until Trump was elected.

“My generation of women took their eye off the ball. We thought the battles were won,” she said. “When he got elected, I was so angry. I felt so defeated.”

So Woolworth joined a local women’s branch of the Democratic Party and banged on doors to get Davids elected in 2018. She was also out campaigning in local elections last week.

“You’re already seeing the independents here stepping back from the Republican party. I think it’s because Trump keeps speaking,” she said.

Woolworth thinks the impeachment process will evolve into a political test for Republican members of Congress from midwestern states.

“Once people have heard the evidence, they will be judged by voters over how they voted on impeachment,” she said.

Some people will not take very much convincing.

Kent Tyler, an artist who voted for George W Bush and then Barack Obama, regards Trump with disdain but is waiting to see what the impeachment hearings reveal.

“Before I make up my mind, I want to see what will come to light. I think it’s very important,” he said. “I call myself a conservative Democrat. I used to be in the middle. Undeclared. Once Trump got into office, and he started doing his stuff, I switched to Democrat. Things need to be brought to light. I think the evidence is going to be very damaging.”

Still Tyler worries about what the impact of the hearings on an already divided country.

“So much hate has been made in America, I think it’s going to get very nasty,” he said.