Current status: Formally announced

Age: 58

Best known for: Serving as New York City’s mayor since 2014.

Biggest strength: The leader of the nation’s biggest city will be able to cite accomplishments such as expanding full-day prekindergarten citywide and curtailing police tactics that critics said were discriminatory, while presiding over continued drops in violent crime.

Biggest weakness: He faces skepticism even at home, with a recent poll finding 76% of New Yorkers say they believe he shouldn’t run. He could also face obstacles in trying to distinguish himself in a field crowded with left-leaning Democrats.