Mayor Bill de Blasio does not think there are enough Democrats in Brooklyn.

So come summer of 2016, he is hoping to import about 35,000 more.

The de Blasio administration on Friday proposed that when the Democratic Party gathers to crown its next presidential nominee, it do so in the mayor’s home borough, a cradle of the resurgent left that has morphed from a symbol of the working class into a gritty, global arbiter of cool.

In a 200-page formal bid, New York City offers up the Barclays Center, the rust-glazed sports and entertainment arena near Brooklyn’s bustling downtown, as the anchor venue for the quadrennial gathering, with accommodations and other events to be spread across the city’s four other boroughs.