With his stunning Super Tuesday wins, Joe Biden is now the odds-on favorite to become the Democratic nominee. Bernie Sanders, the last man in Biden’s way, now finds himself as he did in 2016: one-on-one against a former member of the last Democratic administration. Several candidates dropped out this week, and one joined the race. His name is Barack Obama.

Now that the campaign has settled into a two-man contest, the central issue, which was not inevitable, has emerged. Do Democrats want a return to the less radical era of private health-care options and free trade? Or do they want a new Democratic Party in Bernie’s image that nationalizes whatever it can get its hands on and engages in protectionism and Green New Deals?

In some ways this mirrors the dueling Democratic narratives that emerged from the 2018 midterms in which they took back the House of Representatives. The popular narrative shouted from the covers of political and cultural magazines and on social media was that minority women like Rep. Alexandria Ocasio-Cortez in Queens had spoken truth to Donald Trump’s power and beaten him.

The narrative inside politics was that moderate Democrats like Max Rose in Staten Island had flipped swing districts and that, although unsung, were the real heroes of 2018. This dichotomy, between the radical green left and the less radical purple right of the party, will be front and center in the primary battle.

Had one of the fresh faces, an Amy Klobuchar or Pete Buttigieg, emerged as the stopper of Sanders’s socialism, this election would not be so focused on whether Obama and his brand of liberalism still lies at the core of the Democrat Party. But now it is about little else. So much of Biden’s message is connected to his time with his good friend Barack that it could scarcely be otherwise.

Every now and then in American politics, we see a hostile takeover of a major party. One could argue that Bill Clinton, a Southern “conservative” Democrat, executed such a takeover in 1992, being nominated by the party that had put up Massachusetts liberal Michael Dukakis just four years earlier. Obviously the most recent example is Trump’s bear hug on the GOP, which has transformed it in myriad ways.

Sanders is attempting such a takeover. He has been since he announced his candidacy against Hillary Clinton in 2015. While Sanders is running ads now, as Mike Bloomberg did, showing him being praised by Obama, his political philosophy runs counter to Obama’s “slow march forward” approach. It was Obama, after all, who tried to convince AOC and the Squad last year that change comes dropping slow.

The conventional wisdom right now (and that could change before you finish your coffee) is that Biden is the clear frontrunner. If that is true and he secures the nomination, then it will be up to him to woo Sanders voters who didn’t exactly take a shine to Hillary Clinton. This may take the form of “Hey, I’m better than Trump,” or it may take the form of winking at them as Obama did in 2008 on gay marriage, and saying I’m just saying what I have to say to get elected.

If Biden comes out of the convention as the nominee to challenge Trump, it will still be a referendum on Obama. There the stark contrast and question will be between America under Obama and America under Trump. Our last two presidents — both of whom attracted more deep love and disapproving ire than any of their recent predecessors — will have their administrations pitted against each other.

Obama is back, whether he wants to be or not. He doesn’t have to endorse anybody; it is now clear that Biden is the candidate who represents his legacy. Sanders is the candidate who would erase many of Obama’s achievements and create his own history as the first socialist American president.

It is far from clear where this will all land, but we are in a different place than we were last week. Obama is on the ballot. And that might change everything.