U.S. Sen. Cory Booker ended his presidential campaign Monday.

Booker, a Democratic senator from New Jersey, ended his campaign only 24 hours from the latest presidential debate in Des Moines, Iowa, and less than a month before the Feb. 3 Iowa caucuses.

Booker is the latest Democrat to drop his effort for his party's 2020 White House nomination, following Marianne Williamson last week and Julián Castro earlier this month.

Booker's fellow senator from California, Kamala Harris, ended her bid in early December. Former Congressman Beto O'Rourke dropped out this past October.

As Democrats continue their fierce competition for the minority vote, Booker’s withdrawal leaves the list of remaining candidates even more dominated by older, white people, with former Vice President Joe Biden; U.S. Sens. Bernie Sanders and Elizabeth Warren; and South Bend, Indiana, Mayor Pete Buttigieg leading in many polls and fundraising.

Gabbard, Booker to skip upcoming December debate

Former Massachusetts Gov. Deval Patrick is the only African American still in the race, while Castro was the only Latino candidate seeking the nomination.

Six Democrats will debate Tuesday night, but Booker had yet to meet the polling threshold to qualify. He also did not qualify for the December Los Angeles Democratic debate but was on the stage in Atlanta at the Tyler Perry Studios debate.

Since launching his campaign last February, Booker struggled to raise the type of money required to support a White House bid. He had also warned the looming impeachment trial of President Donald Trump would deal a “big, big blow” to his campaign by pulling him away from Iowa.

He hinted at the challenges facing his campaign last week in an interview on The Associated Press’ “Ground Game” podcast.

“If we can’t raise more money in this final stretch, we won’t be able to do the things that other campaigns with more money can do to show presence,” he said.