Every four years, Michael Bloomberg hears something nobody else hears: a groundswell of support for a Michael Bloomberg presidential candidacy. Now, it’s happening again.

Bloomberg, the media mogul with an estimated worth of $48 billion, announced on Wednesday that he has changed his political registration to Democrat. That makes a full circle for the former New York City mayor, who began as a Democrat, became a Republican, became an Independent, and has now returned home.

‘Today, I have re-registered as a Democrat — I had been a member for most of my life — because we need Democrats to provide the checks and balance our nation so badly needs,’ Bloomberg wrote in an Instagram post announcing his move.

Democrats are welcoming Bloomberg — and his checkbook. The New York Times reported that party leadership has ‘very much embraced’ him. Of course, that was after he promised to contribute $100 million to the party’s midterm elections effort. If you give the Democratic Party $100 million, they will very much embrace you too.

In his announcement, Bloomberg didn’t actually say he will run in 2020. Rather, political observers interpreted his return to Democratic ranks as a necessary first step for a 2020 campaign, so stories about his decision were framed in terms of presidential politics. And for some political reporters who’ve been around the game, it’s virtually muscle memory to report that Bloomberg is mulling a run for the White House.

Bloomberg himself has encouraged such speculation. ‘It’s impossible to conceive that I could run as a Republican — things like choice, so many of the issues, I’m just way away from where the Republican Party is today,’ he told the Times in September. ‘That’s not to say I’m with the Democratic Party on everything, but I don’t see how you could possibly run as a Republican. So if you ran, yeah, you’d have to run as a Democrat.’

As all politicians do, Bloomberg told the paper he was concentrating on the next election, meaning the November 6 midterms. ‘After that I’ll take a look at it,’ he said.

Since Bloomberg has never actually run for president, there is no polling from a previous race to measure his stature as an actual candidate. But in early 2016, when some voters were unhappy with a choice between Donald Trump and Hillary Clinton, the firm Morning Consult asked voters who they would support in a three-way race between the Republican, the Democrat, and Bloomberg, who was then an Independent.

Bloomberg received the support of eight per cent of Democrats, eight per cent of Republicans, and 18 per cent of Independents — not a particularly strong hand.

Morning Consult also found that 43 per cent of all respondents had never heard of Bloomberg or didn’t know enough about him to have an opinion of him. (Among Democrats, the number was even higher: 47 per cent.)

Bloomberg reportedly commissioned his own poll on his viability as a third-party candidate at around the same time. The results of that are not known. What is known is that he did not run.

Now, Bloomberg is mentioned on long lists of possible 2020 candidates. But that is mostly a reflection of his wealth. If he wanted to run, he could pay for a campaign without asking anybody, so he doesn’t have to pass the threshold test of having actual support. Thus his presence on the lists.

But even $48 billion might not convince Democratic regulars that Bloomberg is one of them. Shortly after the new speculation began, a New York City Council Republican, Joseph Borelli, listed the things Mayor Bloomberg did that won’t sit well with national Democrats. Bloomberg spent a lot of time dumping on Barack Obama. He was a big supporter of stop-and-frisk police techniques, now anathema among Democrats. He was tough on Occupy Wall Street. He didn’t get along with organised labour. And more.

And nobody liked the way Bloomberg became what the Times called the city’s ‘nutritional nag.’ Bloomberg cracked down on popular sodas, he banned trans fats, he pushed restaurants to cut their use of salt. And on top of it all, he was a complete hypocrite about it. ‘Mr Bloomberg likes his popcorn so salty that it burns others’ lips,’ the Times noted. ‘He sprinkles so much salt on his morning bagel ‘that it’s like a pretzel’…[and] not even pizza is spared a coat of sodium.’

It all earned him the title ‘Nanny Bloomberg,’ which is probably not the most appealing nickname for a presidential candidate, even in the Democratic Party.

One last thing. Just as the Bloomberg will-he-won’t-he game is getting old, Bloomberg himself is getting old. He will be a few weeks shy of 79 years old on Inauguration Day 2021. In the last race, voters had a choice between the two oldest candidates ever, Clinton at 69 and Trump at 70. There were reasonable concerns about their age and health. And Bloomberg would be elected pushing 80?

Still, look for the stories to continue. If the past is any guide, Bloomberg will toy with the idea of running for at least another year or more. Of course, in the end he won’t, but he’ll keep the political world talking about Michael Bloomberg for a little longer.

Byron York is the Chief Political Correspondent for the Washington Examiner.