Over the weekend, liberal billionaire and former New York City Mayor Michael Bloomberg ended weeks of speculation with the announcement that he would join the crowded 2020 Democratic presidential primary field.

Now the question is how much he'll want to focus his efforts on gun control, given his long history of fighting against Americans' Second Amendment rights.

As the founder of Everytown for Gun Safety, as well as a major financial backer of it, Bloomberg has already built himself quite a resume as a leader in the anti-gun movement. Bloomberg's Everytown also provided seed money to start up The Trace — an anti-gun nonprofit media organization — back in 2015. And years before that, he was a leading voice for the banning of so-called "assault weapons" and "high-capacity ammunition clips" (by which he probably meant magazines).

So, given his background, the question really isn't whether or not Michael Bloomberg will be a pro-gun control 2020 candidate. The question is whether or not he will make his signature issue of the past few years the signature issue of his campaign, and whether or not it'll actually work for him.

The Democratic presidential field has already seen the failure of two virulently anti-gun candidates who made infringement of the Second Amendment a centerpiece of their campaigns: Rep. Eric Swalwell, Calif., and former Texas Rep. Robert "Beto" O'Rourke. Bloomberg certainly has a longer resume and more money than either of them, but it remains to be seen whether either of those would make a difference.

Furthermore, he's going to have a harder time selling his message since his anti-gun bona fides are already tainted on the Left due to the controversy surrounding his "stop, question, and frisk" enforcement plan when he was still running things in the Big Apple. He formally apologized for the policy, but as the Manhattan Institute's Rafael Mangual explains, "if he continues backing away from his record in New York, he'll severely undermine one of his main arguments for sending him to Washington."