Joe Biden was less architect than inheritor of his stunning electoral comeback. His sweeping victory in South Carolina was largely orchestrated by the forceful South Carolina Representative James Clyburn. Then the Democratic establishment went all in.

Amy Klobuchar and Pete Buttigieg got out of the way. Despite a campaign bereft of compelling message, money, or structure, Biden swept to victory in 10 of 14 states on Super Tuesday, ending the day as the party’s front-runner.

Central to his revival was “electability,” the belief that he is the best candidate to beat Trump. Exit polls indicated that majorities in all Super Tuesday states cared more about that than about supporting someone who agrees with them on the issues. Biden won almost twice as many as those voters as Sanders. Democrats voted with their heads, as they say, not with their hearts. Only they got it wrong. The notion that Biden is the stronger candidate against Trump is simply wrongheaded.

Part of that weakness is personal: Long a famous and self-described “gaffe machine,” Biden clearly has lost more than a step. His penchant for serving up malaprops, falsehoods, fumbles, and delusions will provide grist for Trump’s jibe that Biden’s not all there, even while partially neutralizing Trump’s brazen dishonesty.

Similarly, Trump’s campaign will make certain we hear about how Biden’s family—most notoriously, Hunter Biden—has profited from Biden’s prominence, counterbalancing Trump’s egregious use of his office for self-enrichment. But Biden’s true weakness isn’t his personal performance; it’s his record as a politician.

Trump’s major vulnerability is that his populism on the stump was and is his biggest con. As president, he’s signed off on the traditional right-wing agenda of the Republican Party—from tax cuts for the rich to packing the courts with pro-corporate reactionary judges, to throwing money at the Pentagon—while hosting a predators’ ball in Washington.

Trump now touts an economy—the “best ever”—that still does not work for working people. Trump pledged to end the forever wars, but to date has only added troops to conflicts in the Middle East. He boasts of his trade wars, but so far his maneuvers have been more show than substance. His purblind denial of the threat posed by climate change is an astounding dereliction of duty.

Bernie Sanders, if nominated, would turn the election into a referendum on Trump, exposing the big con, while offering Americans a true populist alternative. Sanders’s consistent record of fighting for working people and against the corporate trade treaties, his opposing the Iraq War and leading the effort to bring the wars to an end give him credibility to make the case.

Joe Biden? Not so much.

Biden is the establishment candidate, with a record to match, one that has been wrong—often disastrously so—on fundamental questions over the past decades.

Known as “the Senator from MBNA,” Biden was a champion of financial deregulation—including the repeal of Glass-Steagall—that contributed directly to the financial wilding and the Great Recession. One of his proudest legislative accomplishments, the 2005 bankruptcy bill, was labeled “perhaps the most anti-middle-class piece of legislation in the past century.” It priced bankruptcy out of the reach of most families in distress and made it harder to settle credit card or student loan debts, opening the floodgates for aggressive private student loan lending and credit card peddling.

In the 1980s, Biden made balanced budgets his cause, issuing stark warnings about the dangers of deficits, and preening about his willingness to cut Social Security and Medicare to bring deficits under control.

In the 1990s, Biden was cheerleader for the corporate trade deals—NAFTA, China in the WTO, and later Obama’s Trans Pacific Partnership—that encouraged companies to ship jobs abroad, and contributed directly to the stagnation of workers’ wages.

As chair of the Foreign Relations Committee, Biden applauded Bush and voted for his war of choice in Iraq, surely the biggest foreign policy debacle since Vietnam.

Cumulatively, this record of failed judgment has profound political effect. It will enable Trump to replay the campaign he ran against Hillary Clinton, posing as a populist insurgent against a failed establishment that enriched itself even as it failed working people. Trump will be the candidate of change against Biden, the admitted candidate of restoration.

Unlike 2016, Trump will marshal a sophisticated campaign operation, with an unprecedented social media reach, an independent communications capacity, an array of outside allies, and virtually unlimited money. He will use this to hone attack messages aimed at Biden’s strongest areas of support. And Biden’s history makes him particularly vulnerable to those tactics.

Biden, an early opponent of busing, has a history of unfortunate statements on race. As chair of the Judiciary Committee in the 1980s, he was instrumental in the passage of harsh crime bills that resulted in the grotesque mass incarceration that disproportionately hit African American men. Biden’s strongest support in the primaries has been from African Americans. Trump’s campaign will target them directly, hoping to suppress turnout or lower support for Biden.

Biden’s “handsiness” weakens any attack on Trump’s grotesque record with women. Worse, his infamous treatment of Anita Hill in the Clarence Thomas hearings and his mixed record on choice—he was a longtime supporter of the Hyde Amendment and its offshoots that made abortions less available to poor women—will likely be used by spurious independent groups to soften Biden’s support among women.

Similarly, Biden’s votes to lower deficits by cutting Social Security will become a weapon to reduce his support among seniors.

In contrast, Sanders has been a consistent champion of civil rights from the beginning, and a strong supporter of choice, of equal pay for women, of universal day care. His forceful advocacy of tuition-free college and of a Green New Deal are major reasons he has overwhelming support from young voters.

Sanders would be more coherent on the stump and more forceful in the debates. He is less likely to be flummoxed by Trump’s insults and jibes.

His record makes him a credible populist voice, one able to expose Trump’s broken promises to working people. He is likely to help spur a record turnout among young people. Trump’s campaign will rant about Venezuela, communism, radicalism. But Sanders’s consistent advocacy over many years, his invocation of FDR, are likely to deflect these attacks.

Why have establishment Democrats rallied so forcefully in favor of Biden? Perhaps they are making the same bet they made in 2016: that for every blue-collar vote lost with an establishment candidate, the party can pick up two from suburban women offended by Trump. Sanders’s radical agenda might put that support at risk. That wager turned out to be a bad one in 2016, when Trump was running a makeshift campaign against the well-funded Clinton juggernaut, with its historic attraction to upscale suburban women. Is it likely to fare better in 2020, when Trump’s operation is far more sophisticated, and Biden far less exciting?

Or perhaps establishment Democrats are rallying to Biden less from confidence in his candidacy than from fear of Sanders’s rise. For all the hand-wringing about Trump’s assault on democracy, they may well prefer to lose to Trump than to lose control of the party to Sanders.

That’s not a choice that the overwhelming majority of Democratic voters would make. Over the next weeks, Biden’s record will get more scrutiny. Biden and Sanders will face off in a debate. Voters will get a far better look at which of the two they think could fare well against Trump. They might do well to take another look.