Michael Bloomberg, the eighth richest man in the United States and the former three-term mayor of New York City, has given himself until March to decide whether to run as an independent for president. By then, reports say, he’ll be able to get a sense of whether Bernie Sanders has a shot of getting the Democratic nod, and whether Donald Trump or Ted Cruz will nab their party’s nomination. While Bloomberg may not run, the mere mention of his candidacy could have profound political consequences.

This isn’t Bloomberg’s first flirtation with self-funding a presidential campaign — he’s explored the possibility with advisors since 2006. Bloomberg fancies himself the radical centrist, the educated adult in a world where Republicans have become unhinged culture warriors and the Democratic base is warming to economic populism.

Supporters gush that he built one of the world’s most successful companies and ran America’s financial capital for twelve years. That he’s got the know-how to manage, the ability to pick talented people to run departments, and the wisdom to support liberal positions on social issues like gun control and abortion rights. His ideology is sensibility, and with his wealth he literally cannot be bought off.

Even many New York City Democrats, exhausted by the corruption and cronyism of machine politics, like Bloomberg’s independence. They note that he switched his partisan affiliation from Democrat to Republican before launching his mayoral bid.

Worth nearly $40 billion now, Bloomberg made his fortune by controlling the supply chain — his terminals are essential in the finance industry. From there he grew into a media mogul. Elected to his first term in November 2001, Bloomberg pushed for bans on trans fats and smoking indoors. He was well liked by some because he was able to extend the trend of declining crime and increasing private investment.

But bike lanes and glittering residential projects in once-blighted areas came at a cost. He battled labor unions, famously referring to the 2005 transit strikers as “thuggish,” and by the time he left office he had cut off collective bargaining with city unions altogether. His stop-and-frisk policing, along with the surveillance of Muslim communities, gave the impression that his social liberalism only applied to affluent white people.

Indeed, rather than trans fat bans or smoking restrictions, heavy policing and attacks on organized labor were at the heart of the Bloomberg political vision. So it was no surprise that Bloomberg expressed frustration at the ascendance of Bill de Blasio, who vowed during his campaign to shrink the chasm between rich and poor New Yorkers. Now along comes Bernie Sanders, whose social-democratic vision is anathema to Bloomberg’s entire political project.

So he’s been forced out of political retirement to act.

Let’s get one thing out of the way: Bloomberg will not be elected president if he runs. For one, he’s haunted by history: no New York City mayor has gone on to higher office. Bloomberg wouldn’t stand much chance of breaking that streak. Aloof and patrician, his appeal is limited to moderate liberals in capital-rich cities. It’s difficult to imagine one of Bermuda’s most prominent weekenders sipping coffee at a diner with voters in Peoria.

Despite his reputation, Bloomberg’s tenure also ended on a series of down notes. He had to mount a vigorous reelection campaign for a third term, despite facing a charisma-deficient Democrat who barely bothered to seriously compete. Then he allowed a once-obscure scandal involving troubled contracts for a new city time-keeping system to bubble to the public view, sullying his image as a clean and cold-eyed manager. And his crusade against large sodas became late-night joke fodder.

What Bloomberg can do, however, is scare Sanders-leaning progressives by playing the spoiler. Judging from the Clinton campaign’s recent barrage of attacks, the former secretary of state is increasingly nervous about her chances in the early contests. Sanders has an edge in New Hampshire and could very well beat her in Iowa. Clinton’s support also looks to be slipping among African-American voters in South Carolina, her purported “firewall.”

Bloomberg is astute enough to know Clinton is the only viable Democratic candidate who can be trusted to advance Wall Street-friendly policies. He sees her close race with Sanders and the FBI investigation concerning her emails as reasons to worry about the political future. As for the Republicans, Cruz is untethered from the establishment, and Trump refrains from attacking Social Security, says he wants to bring back manufacturing, and stokes white nationalism.

Bloomberg’s play would be to step into a Clinton-less general election and sop up moderate Democratic and Republican votes in key states. For many progressive Democrats, the risk of throwing the election to a Cruz or Trump would be too much: Sanders might be better than Clinton, but getting behind her becomes the only prudent thing to do when Ted Cruz is outside the White House gates. Bloomberg is exploiting this anxiety to ensure the Sanders surge is nothing but a brief phase.

Here’s a man in the autumn of his life, ostensibly willing to run an unsuccessful campaign with $1 billion of his own fortune just to scare enough primary voters away from a septuagenarian social democrat. In Sanders, Bloomberg sees a surprisingly electable candidate speaking to many of the same grievances as Occupy Wall Street — a movement Bloomberg harassed and expelled with intense police violence.

Left critics of Sanders point out that he’s more social democrat than socialist, or argue he’s sheep dogging for the Democrats. But Michael Bloomberg knows which side he’s on, and he’s rattled. That alone says something about the moment we’re in, and the possibilities for progressive change.