Sen. Bernie Sanders will swing through Pennsylvania, Wisconsin, and Michigan this weekend, his campaign said, as the Vermont senator seeks to make the case that he is the Democratic candidate best positioned to win back key states that helped deliver to Donald Trump the presidency.

The announcement Monday is the latest sign that in addition to trying to win the battle of ideas in the Democratic race, the candidates believe they must show that they can beat Trump in 2020. Primary voters place a higher priority on beating Trump than on ideological purity, according to a February Monmouth University poll.

Sanders, a self-described democratic socialist, is to hold a rally in Pittsburgh on Sunday, following trips to Madison, Wis., and Warren, Mich. The Pittsburgh event is scheduled for 5 p.m. at Schenley Plaza, near the University of Pittsburgh campus.

Winning those three states plus each one carried by Hillary Clinton in 2016 would hand the Democratic nominee more than the 270 Electoral College votes needed. Trump won Pennsylvania, Michigan, and Wisconsin by a total of fewer than 80,000 votes.

“Sanders will deliver a message focused on fighting against unfair trade deals that undermine workers’ wages and enrich CEOs, rebuilding and strengthening unions, and guaranteeing health care as a right to all with Medicare for All,” the campaign said.

With a devoted following he gathered running against Clinton, Sanders says he has raised $18.2 million in the first six weeks of his presidential campaign, far outpacing his rivals. The campaign said last week the average donation was $20.

In a strategy memo Monday, Sanders campaign manager Faiz Shakir argued that winning back the three states Sanders will visit this weekend presents Democrats with the clearest path to the White House — and that Sanders is the best candidate to do it.

“Voters in these states, across many demographic groups, are looking for a message that understands the deep, unaddressed concerns of working families, and shows a commitment to fighting against the decades of policy in Washington that have led to job loss, closed factories, and hollowed-out local economies,” Shakir wrote.

He pointed to polling showing early support for Sanders in these states, which Shakir said was driven by “a unique, authentic message about trade, unions, working families, and health care.”

Sanders’ trip comes a few weeks after Beto O’Rourke, the former Texas congressman who lost a close race to unseat Sen. Ted Cruz last year, made a campaign stop in State College.