Elena Moore

Three days before the Nevada caucuses, six Democratic candidates will face off in a debate Wednesday night in Las Vegas.

The televised debate comes on the heels of a new NPR/PBS NewsHour/Marist Poll that shows Vermont Sen. Bernie Sanders leading nationally, with 31% support among Democratic-leaning voters.

Trailing Sanders in second in the survey is billionaire and former New York City Mayor Michael Bloomberg, with 19% backing.

After a flawed Iowa caucus process, the Senate acquittal of President Trump and a dramatic State of the Union address — all in the past five days — Friday night brings the eighth Democratic presidential debate.

President Trump ordered an airstrike on Thursday evening that killed the Iranian General Qassem Soleimani in Baghdad, a man he said was "plotting imminent and sinister attacks" against Americans in the region.

Soleimani was the leader of the Quds Force, a covert section of the Islamic Revolutionary Guard Corps. The White House says he was the mastermind behind attacks on Americans during the past two decades — including two recent attacks.

Updated at 10:30 a.m. ET

Julián Castro, the only Latino candidate in the Democratic field, has ended his presidential campaign.

Castro released a video on Twitter on Thursday, saying that his campaign had "stood up for the most vulnerable people" and had "given a voice to those who are often forgotten."

He adds in the video: "I'm not done fighting. I'll keep working toward a nation where everyone counts."

Castro served as secretary of housing and urban development in the Obama administration and, before that, was mayor of San Antonio, Texas.

The top seven Democratic presidential candidates will appear on stage in Los Angeles Thursday night in the sixth debate of the year.

The debate comes just one day after President Trump became the third president of the United States to be impeached by the House of Representatives.

Here's what you need to know: