Trump mocks Democrat for dropping out of presidential race.

U.S. President Donald Trump mocked Sen. Cory Booker's withdrawal from the Democratic primary, tweeting sarcastically that he would be able to "rest easy tonight."

He recalled that Booker was in zero polling territory. "Now I can rest easy tonight. I was sooo concerned that I would someday have to go head to head with him!" Trump tweeted.

Booker announced earlier Monday that he would suspend his presidential campaign. He failed to qualify for the last Democratic debate and did not meet the threshold to participate in Tuesday's debate, and the senator acknowledged he did not see a path to the nomination.