Vermont Senator Bernie Sanders is now the frontrunner in the 2020 Democratic presidential primary.

Hot off the heels of winning the popular vote in the contentious Iowa caucus, Vermont Senator Bernie Sanders is in the best position of his campaign. He is polling well against, if not ahead of, longtime frontrunner Joe Biden in important early primary states like New Hampshire, Nevada, and California. Rising on a tide of donations averaging around $20 a piece, Sanders has forced the Democratic establishment and the news media to reckon with the real prospect of his nomination.

This is great news for anyone who wants to see Donald Trump evicted from the White House. Sanders’s strengths as an independent populist play perfectly well against Trump’s weaknesses as a corrupt, incompetent billionaire. Trump’s strongest argument, which has been to paint his opponents as Washington insiders, fall flat against Sanders, a sincere outsider whose convictions have held over his long career.

Perhaps Trump’s greatest gift as a politician is his ability to dispatch an opponent using only a single phrase or nickname: “Lyin’ Ted,” “Low-energy Jeb,” or “Crooked Hillary.” It’s childish bullying, but it’s effective. Elizabeth Warren has demonstrated that Trump can bait her into public embarrassment. Biden has no comeback to “Sleepy Joe” or “Where’s Hunter?”; his deteriorating mental state and family corruption are matters of fact. Sanders, on the other hand, owns the “socialist” label and makes it palatable to an America beset by longer hours, harder work, and runaway inequality.

Trump knows that Sanders is his toughest opponent. In leaked audio from April 2018, Trump admits Hillary Clinton would’ve been stronger with Sanders as her vice president, saying, “He was the only one I didn’t want her to pick.” Trump reportedly grapples with the appeal of socialist policies, telling advisers that the cancellation of student debt is “a tough one to run against.” He even offered faint praise for Sanders in his Super Bowl interview, saying, “At least he’s true to what he believes.”

Sanders is fighting for healthcare, a living wage, debt reduction, and tuition-free college for everyone in America. Within the current Washington dynamic, those policies are written off as unrealistic or too extreme despite their popularity across a broad swath of the American people. Even those who support Sanders and his policies often fear that his progressive agenda will never pass through a far-right, obstructionist Congress. In order to overcome gridlock and establishment opposition, Sanders has pledged to govern as an organizer-in-chief, encouraging Americans to keep the pressure up on elected politicians.

Much of the media have declared Sanders and South Bend, Indiana Mayor Pete Buttigieg co-winners of the messy Iowa Caucus. Sanders beat Buttigieg by some 6,000 popular votes, but they will likely receive the same number of delegates.

Even if he doesn’t pass his entire legislative agenda, Sanders has gotten the nation talking about it. Moderate Democrats like Pete Buttigieg now have to make their arguments against Medicare for All. In addition to his New Deal-like domestic policies, Sanders is the most antiwar candidate running and the most aggressive on climate change. Dozens of nations outperform America in healthcare, education, housing, labor rights, and/or environmental protection, and Sanders has shifted the national conversation toward doing better.

Sanders’s biggest obstacles may well come from his own party. Hillary Clinton questioned Sanders’s electability and recently said, “Nobody likes him… nobody wants to work with him.” Insider reporting suggests that Barack Obama, John Kerry, and other top Democratic figures desperately want to avoid a Sanders nomination. Billionaire Howard Schultz has threatened a third-party run if Sanders is the nominee and Michael Bloomberg has already spent some $200 million on his own campaign.

The problem isn’t that Sanders is unelectable; he consistently polls well against Trump, and better in many polls than any other Democrat. The problem is that the Clinton wing of the party doesn’t like him. A Sanders presidency may threaten the interests of corporate Democrats even more than a Trump presidency, fraying their close relationships with wealthy donors. So much the better for ordinary Americans, as those relationships have turned the party away from working-class interests.

Hillary Clinton’s 2016 campaign is most instructive of all. Her campaign focused more on the evils of Trump than the good she planned to do. Though she won the popular vote, she lost the election. To rally the support and enthusiasm necessary to retake the White House and move America forward requires an inspirational message of your own.

Sanders has no misunderstandings about the danger posed by Trump’s corruption, authoritarianism, and bigotry. But Sanders also knows that Trump cannot be the only focus. The Sanders campaign is centered around class solidarity, environmental innovation, and social supports to guarantee every American a fundamental standard of dignity. That message has made him the Democratic frontrunner. Not only is Bernie Sanders the best choice to stop Donald Trump, he is the best president for this moment.