Former Vice President Joe Biden landed a series of major endorsements from high-profile Democrats Monday, including former 2020 competitors who ended their campaigns to get behind the establishment favorite.

Just 48 hours before the nationwide contests on Super Tuesday, former South Bend, Indiana Mayor Pete Buttigieg dropped out the race and announced his endorsement for Biden in Dallas Monday night. Sen. Amy Klobuchar, who ended her campaign earlier in the afternoon, also endorsed Biden on the Dallas stage along with yet another former Democratic candidate, former Texas Congressman Beto O’Rourke. On the same day, Biden also secured endorsements from former Democratic Senate Majority Leader Harry Reid and former U.N. Ambassador Susan Rice.

The slew of endorsements on the eve of the biggest day of the Democratic primary illustrates a “moderate” coalescing around Biden following a 28-point blow-out win in South Carolina that has resurrected his sunken campaign and offered new hope to Democrats seeking to thwart Vermont Sen. Bernie Sanders’ momentum. As the Biden campaign suffered blow after blow by performing worse-than-expected in the first three contests, Sanders eclipsed Biden as the new frontrunner. Sanders captured the popular vote in Iowa, took home first place in New Hampshire and claimed victory in Nevada by 26 points, all while the Biden campaign went into free-fall, hinging its bets on South Carolina as its “firewall.”

It’s no secret President Barack Obama is anxious about a Sanders nomination. Last fall, the former president, who has refrained from getting involved in the Democratic contest, privately remarked that he would speak out if Sanders appeared likely to capture enough delegates needed for the party’s coronation in Milwaukee.

Now, as Sanders reels into Super Tuesday high off of his February momentum, Biden’s revived campaign may be the Democrats’ only bet to break the seemingly unstoppable Sanders surge to the nomination without facing a contested convention this summer.

Sixteen states and territories are casting their votes for the Democratic primary today, where more than a third of the total delegates in the race will be decided. If Obama had anything to do with lining up the streak of game-changing establishment endorsements for Biden on the eve of the most consequential day of the primary, he should step off the sidelines and explain why rather than pulling strings from behind closed doors.

This time, then, efforts from power players within the Democratic Party working to block Sanders again would be made in plain sight. One way or another, Obama’s influence in the race is certain to emerge in the press at some point, whether it’s before the November election or after. In 2017, former Democratic National Committee Chairwoman Donna Brazile accused 2016 nominee Hillary Clinton of orchestrating a “secret takeover,” of the DNC as the primary got underway.

This year, Sanders appears to be up against some of the same forces that offered resistance to his campaign four years earlier. Sanders was pulled off the trail in the days leading up to Iowa for an impeachment trial that House Speaker Nancy Pelosi delayed for weeks that just so happened to land proceedings in the final two weeks before the caucuses. Sanders had to defend himself against former New York City Mayor Michael Bloomberg’s attacks on the Vermont senator for championing “communism” on the Las Vegas debate stage, after the DNC changed the rules to allow Bloomberg on stage. Now it appears that Sanders is running up against the rest of the entire Democratic establishment that has united against him with Biden as their vehicle.