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.

Writer, entrepreneur and spiritual leader Marianne Williamson has ended her presidential campaign, months after garnering viral attention in early debates, earning curiosity but little support from Democratic voters.

"The primaries might be tightly contested among the top contenders, and I don't want to get in the way of a progressive candidate winning any of them," Williamson wrote in a letter to supporters. "As of today, therefore, I'm suspending my campaign."

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:

Updated at 2:15 p.m. ET

House Intelligence Committee Chairman Adam Schiff, D-Calif., has released a report that outlines the findings from public hearings and closed-door interviews conducted by impeachment investigators since late September.

As part of the impeachment inquiry, the House Intelligence Committee has released the transcript of the testimony by Philip Reeker, the acting assistant secretary of state who is responsible for European affairs.

Reeker testified for eight hours on Oct. 26, complying with a subpoena despite pressure from the White House to defy the request.

According to a source familiar with his testimony, Reeker was prevented by high-ranking State Department officials from aiding Marie Yovanovitch, then U.S. ambassador to Ukraine, before she was recalled from her position.

House impeachment investigators have released the transcript of the deposition of Mark Sandy, a career staffer for the White House Office of Management and Budget.

Sandy was deposed by lawmakers on Nov. 16 and was the lone person from the OMB to testify. Top-ranking political appointees to the OMB — including Russell Vought, its acting director — refused to comply with the investigation's requests, citing advice from the White House counsel's office.

Two more witnesses testify Thursday morning in front of the House Intelligence Committee, marking the end of this week's public impeachment hearings.

Fiona Hill, the former Russia director for the National Security Council, and David Holmes, a U.S. diplomat from the U.S. Embassy in Kyiv, are appearing before investigators.

Over the past three days, lawmakers have spent hours questioning a total of nine U.S. officials (including Hill and Holmes).

No additional hearings have been announced by the Intelligence Committee.

Fiona Hill

Updated at 3:50 p.m. ET

Four witnesses are testifying in front of the House Intelligence Committee on Tuesday, starting the second week of public hearings in the ongoing impeachment inquiry investigation.

The morning session features Jennifer Williams, a career State Department staffer detailed to work with Vice President Pence's staff, as well as Lt. Col. Alexander Vindman, the Ukraine specialist on the National Security Council. Former U.S. envoy to Ukraine Kurt Volker and former Russia director for the NSC Tim Morrison are testifying in the afternoon.

Impeachment investigators have released the testimony transcript of Tim Morrison, the former top European affairs official on President Trump's National Security Council.

In his Oct. 31 testimony, Morrison confirmed he was on the July 25 phone call between Trump and Ukraine's president. He also said that Trump had indeed sought help from his Ukrainian counterpart, but he argued the conduct wasn't unlawful.

The warnings from national security leaders in Washington have been clear: The danger of foreign election interference isn't going away.

What have the many Democratic presidential hopefuls pledged to do about it?