On Thursday night, U.S. Sen. Bernie Sanders did more than just go in front of the cameras for a presidential town hall in Milwaukee.

Before the lights went on, he made another stop, meeting around 70 activists at Coffee Makes You Black on the city's north side.

"The purpose of the meeting was to talk about the problems facing Milwaukee and what a progressive president can do to help cities in distress," Sanders said in an interview Friday with the Milwaukee Journal Sentinel.

Sanders said he heard from the group about poverty, student debt, criminal justice, health care, raising the minimum wage to $15 an hour, and immigration, the kinds of issues he's running hard on throughout the country.

There's obviously a long way to go in the race for the Democratic nomination, which will culminate with next year's convention in Milwaukee. But Sanders, who campaigned for U.S. Sen. Tammy Baldwin and others in Wisconsin in 2018, is methodically laying the groundwork to claim the state next year.

Sanders won Wisconsin in the 2016 primary against Hillary Clinton. And he's attempting to corral the state for a general election battle against President Donald Trump.

Trump has tagged Sanders as "Crazy Bernie."

Sanders said of the president: "Trump is a phony. And he's a fraud. And he's a pathological liar."

"Look, it's not a political secret. But the Midwest is in many ways the key to the 2020 election," Sanders said. "Trump won Wisconsin by a very narrow vote, but he won."

In 2016, Sanders provided a left-wing alternative to Clinton. Since then, a big chunk of the party has moved his way, with other presidential candidates attempting to flood a progressive zone he once had to himself.

The field is crowded and Sanders is looking for running room. He said he wants a campaign "based on ideas and record" and has strong relationships with a lot of the other candidates.

Former Vice President Joe Biden remains the front runner.

"Joe and I have a very different record, and a very different vision for America," Sanders said. "Joe voted for the war in Iraq. I helped lead the effort against that war."

"I voted against the deregulation of Wall Street, which I believe led to the Wall Street crash. Joe voted to deregulate Wall Street and voted for the bailout. I did not vote for the bailout."

Sanders added: "Joe supported NAFTA, permanent normal trade relations with China, I led the effort against those trade agreements. Joe voted for the bankruptcy bill. I voted against the bankruptcy bill. You know, Joe's vision for the future of this country is a very different vision than mine."

Sanders said he wants a Democratic Party that "reflects what the American people want, rather than wealthy campaign contributors."

"Is that really a terrible thing, that we have a party that speaks to the needs of the working class of this country?" he said. "The working class is in deep trouble right now. And I think our job is to represent the working people of this country, not wealthy corporate interests. And if people want to criticize me then criticize me. It's not like I'm coming up with some crazy ideas, you know, the ideas that I'm talking about on this campaign, and that others have adopted, are ideas that exist all over the world."

Not everyone is on board with Sanders' vision of the party. The head of the centrist think-tank Third Way, Jonathan Cowan, made a reference last month to Sanders being an "existential threat" to the future of Democratic Party, according to The Guardian.

"Well, I accept that as a badge of honor," Sanders said. "OK, to his understanding of what the Democratic Party should be, I am an existential threat. Because we want to move the party in a different direction, a party that represents not the Wall Street that he represents, but the working class of this country, the people of Milwaukee, the people who are struggling all over this country."

His signature issue in this race may be his Medicare-for-all, single-payer health care proposal.

"What we need to do over a four-year period is expand Medicare to cover every man, woman and child in this country," he said.

Some of Sanders' opponents oppose a plan that eliminates private health insurance. Republicans have also been eager to pounce on Sanders' proposal.

"What is implicit in a Medicare-for-all system is your right, the right of the American people, to go to any doctor they want, or any hospital that they want," he said. "And anybody who tells you that's not in our program is simply not telling the truth. Now, when we fight for a Medicare-for-all system, we are taking on the drug companies and the insurance companies who will spend hundreds of millions of dollars to protect their profits that prevent us moving in that direction."

To highlight inequities in the U.S. health care system, Sanders plans a trip to Canada with Type 1 diabetes patients who need insulin.

"People who are suffering with diabetes will be able to buy the insulin they need for one-tenth the price that they're paying in the United States," he said. "And the reason for that is that Canada has a national health care system, essentially a Medicare-for-all, single-payer system."