On Tuesday, Senate majority leader Mitch McConnell acknowledged for the first time that Joe Biden won the 2020 presidential race. This was far from a hasty decision, taking place a full 38 days after the election—and a month after most news outlets had called Biden’s victory. The New York Times describes McConnell’s actions as “a clear bid by the majority leader, who is the most powerful Republican in Congress, to put an end to his party’s attempts to sow doubt about the election.”

There’s scant evidence that the GOP will follow McConnell’s lead. In fact, it was notable that House minority leader Kevin McCarthy refused to join in the congratulations. The same day, 26 Republicans freshly elected to the House of Representatives signed a letter asking House Speaker Nancy Pelosi to investigate voting irregularities, indicating they supported Donald Trump’s narrative of a stolen election.

McConnell’s tardy acceptance of reality hardly deserves applause. But Biden, who has been patiently waiting for any signs that Republicans are ready to move on from the Trump era, was quick to salute McConnell’s words. “I called to thank him for the congratulations, told him although we disagree on a lot of things, there’s things we can work together on,” Biden told reporters.

Biden campaigned on the promise to be a national unifier who would heal the divisions created by Trump. During the election, it was unclear whether this was campaign rhetoric aimed at swing voters who like to hear about bipartisan cooperation or a sincere plan on Biden’s part. The fact that Biden continues hitting this theme during the transition suggests that he is indeed making an overture to Republicans.

This is a gambit fraught with risks. The Obama administration was thwarted from the start by a determined campaign of Republican obstruction, led by McConnell. From 2009 to 2015, Obama and Biden wasted much time fruitlessly negotiating with McConnell and sometimes making major concessions to him, in the futile hope that he would relent.

Earlier this summer, Obama told The New Yorker, “Through its actions, the Republican Party has discredited the old-style negotiations and compromises that existed in Congress when Joe first came in. And it’s probably taken him a little time to let go of that.”

But all evidence suggests that Biden still nurses the fantasy of bipartisan comity. Speaking to supporters on a call on Monday, Biden said, “I predict to you, and I may eat these words, I predict you as Donald Trump’s shadow fades away, you’re going to see an awful lot of change.” He added, “I know I’ve been criticized heavily for saying from the beginning, we’ve got to unify the country. I think you’re going to be surprised. It’s going to take six to eight months to get it under way but I think you’re going to be surprised.”

Politico noted that “Joe Biden thinks he’ll succeed where President Barack Obama failed—at least when it comes to Republicans in Congress.” According to the news site, “Biden believes infrastructure and other issues like rural broadband are early openings for some bipartisan agreement (infrastructure week may finally happen!?) and is steering away from issues where the parties are just too far apart. The Biden team also believes the thin majorities in each chamber along with the demographic realignments in both parties offer some chances to pick off votes.”

Adam Jentleson, a former staffer for retired senator Harry Reid, opined on Twitter that Biden is operating on the Green Lantern theory that he has a super power denied to other politicians. “I hope that either Biden is right, and he’s the Green Lantern uniquely able to overcome the massive structural forces pushing Republicans to obstruct, or that he can change course quickly,” Jentleson wrote. “The worst case is chasing the dream long after everyone else knows it’s not happening.”

Jentleson’s skepticism is well grounded. It’s hard to see how this strategy of seeking Republican cooperation could possibly succeed. After all, the Democrats are far weaker in the House than they were from 2009 to 2011 and weaker in the Senate than they were from 2009 to 2015. Political polarization is far more intense now than it was even in the Obama era. According to a Fox News poll, 77 percent of those who voted for Donald Trump believe that the election was stolen.

As president, Biden could try to reach across the aisle, but what is likely to happen is that any Republican who responds favorably will immediately be branded a Republican in name only (RINO) by Trump himself or his many allies in the right-wing media. After all, if Biden stole the presidency, then cooperating with Biden is tantamount to treason. RINO hunting will be a major sport among Trumpists. Elected Republicans will live in fear of primary threats from the MAGA brigade.

Progressives shouldn’t be afraid to play the role of Cassandra in this drama: Right now, they should be warning about the pitfalls of the strategy. Aside from the dubious likelihood of yielding results in Congress, it’s also a self-defeating strategy for a party that desperately needs to rebuild its down-ballot ranks.

If you argue that the Republican Party is on the verge of an epiphany, then you are giving marginal voters permission to stay home and swing voters permission to vote for Republicans. A message of bipartisan cooperation might have helped Biden win the election, but it also demobilizes down-ballot voters. With the crucial Senate races in Georgia only weeks away, Biden is giving aid and comfort—and ammunition—to the enemy.

But beyond electoral outcomes, progressives need to develop a Plan B for what to do when Biden’s strategy fails, as it almost certainly will. They have to keep hammering home the fact that there are enormously consequential policy decisions Biden could make by executive order or through administrative fiat. If the Republicans obstruct economic policy, then the logic of using an executive order to cancel student debt becomes imperative. Taking a page from Trump, Biden could also pressure the Federal Reserve to adopt an easy money policy designed to spur recovery and achieve full employment as soon as the pandemic is over.

In an ideal world, Biden should adopt these policies from day one. Alas, he seems still wedded to the fantasy of bipartisan comity. But that daydream is likely to encounter a rude shock quite soon. The task of the left is to have a plan in place once Biden realizes his preferred mode of governing isn’t going to work.