Former Vice President Joe Biden said Thursday his top priority upon becoming president would be to "defeat Donald Trump."

NBC debate moderator Chuck Todd went down the line of the 10 Democrats on the stage in Miami and emphatically asked what their first issue they'd want to get passed would be in the White House. He noted former President Barack Obama wanted to tackle health care and climate change in his first year but could only get the former accomplished.

When it was Biden's turn, he first took exception to Todd's comments about who he often calls his "buddy," saying Obama had forged a great accomplishment with the Paris Climate Accords.

"The first thing I would do is make sure that we defeat Donald Trump," Biden said. "Period."

Presumably, Biden would already have defeated Trump if he is elected in 2020. Todd, in a hurry, did not press Biden on his comment.

Fellow candidates Rep. Eric Swalwell (D., Calif.), Sen. Michael Bennet (D., Colo.), Sen. Kirsten Gillibrand (D., N.Y.), Sen. Kamala Harris (D., Calif.), and Sen. Bernie Sanders (I., Vt.) went before him and said their first priorities were policies like ending gun violence, addressing climate change, and enacting a Family Bill of Rights.

Biden is the frontrunner in the 2020 polls, but his performance at Thursday's debate was widely criticized, particularly for an exchange with Harris where she went after him for recent remarks about working cordially with segregationist Democrats.