Sen. Elizabeth Warren (D-Mass.) announced Monday that she had formed a presidential exploratory committee, joining former U.S. Secretary of Housing and Urban Development Julian Castro (D) in taking the first steps towards a possible presidential run.

 

Warren has brought on several experienced staffers to her Iowa team from the Clinton, Obama, and Sanders campaigns: Emily Parcell, Janice Rottenberg, and Brendan Summers.

 

More than 440 candidates have already filed with the Federal Election Commission to run for president in 2020, including 133 Democrats, 60 Republicans, 18 Libertarians, and 10 Greens.

 

Ballotpedia is also tracking more than 60 possible Democratic and Republican presidential contenders.