Brett McGurk, the United States' special presidential envoy for the global coalition to counter the Islamic State, tendered his resignation Friday in response to President Trump's decision to withdraw U.S. troops from Syria.

Appointed by former President Barack Obama, McGurk previously planned to leave his post in February, but he will now depart at the end of December. Defense Secretary James Mattis also resigned this week over foreign policy differences with Trump; he will step down at the end of February.

"The recent decision by the president came as a shock and was a complete reversal of policy that was articulated to us. It left our coalition partners confused and our fighting partners bewildered," McGurk reportedly said in an email to his staff. "I worked this week to help manage some of the fallout but — as many of you heard in my meetings and phone calls — I ultimately concluded that I could not carry out these new instructions and maintain my integrity." Bonnie Kristian

MSNBC is getting ready for the historic first impeachment hearing of President Trump with a very special guest making a rare appearance on cable news.

George Conway, who is married to White House counselor Kellyanne Conway, appeared on MSNBC Wednesday morning in the lead-up to the first public hearing in the impeachment inquiry. Though Conway has been a vocal critic of Trump, CNN's Brian Stelter notes he has declined all TV interview requests until now.

Ahead of the testimony of William Taylor, the U.S. charge d'affaires in Ukraine, and Deputy Assistant Secretary of State George Kent, Conway told MSNBC that Trump "always sees himself first" and that this scandal is all about Trump having used "the power of the presidency in its most unchecked area, foreign affairs, to advance his own personal interests as opposed to the country."

Conway also said Congress needs to "do its duty" for the country and that he's "horrified" at how Republicans have come to the president's defense.

"Take that Republican hat off and look at it neutrally," he said. "Or look at what you would have done if Donald Trump was a Democrat. Would you be making these ridiculous arguments about process ... or 'it wasn't corrupt, he was really talking about corruption.' All these things that they don't really believe or couldn't possibly believe."

Conway was, evidently, a reluctant guest, telling MSNBC, "I don't frankly want to be on television." Brendan Morrow

Get your posterboards ready.

It's impeachment hearing time, and while House Republicans didn't enter the floor until 10 a.m., their defense of President Trump sure arrived earlier. Lined up behind the bench Wednesday morning where congressmembers would soon take their seats were a series of posters essentially outlining Republicans' strategy for the day.

On the farthest left of the three posters, Republicans printed a quote from Rep. Al Green (D-Texas). He was the first congressmember to call for impeaching Trump more than two years ago, and at one point said "I'm concerned if we don't impeach the president, he will get re-elected." That's indicative of how Republicans will likely claim Democrats are conducting an impeachment inquiry as a last resort for beating Trump.

That same message is reflected in a blow-up of a a tweet from Mark Zaid, the lawyer for the whistleblower who first raised concerns about Trump's Ukraine dealings. In it, Zaid says a "coup has started" against Trump and that "impeachment will follow," apparently indicating his bias in the matter. And the middle board says it's been 93 days since House Intelligence Committee Chair Adam Schiff (D-Calif.) "learned the identity of the whistleblower," suggesting he's holding back information from the rest of Congress. Kathryn Krawczyk

Republicans have trotted out 17 defenses of President Trump's conduct with Ukraine since a whistleblower accused Trump of extorting the country's president for partisan political gain, according to The Washington Post's count.

The whistleblower's complaint has been mostly corroborated by impeachment witnesses, many of whom will testify over the next 10 days. But in an 18-page memo passed around Monday, Republicans boiled down their defense of Trump to four main points you can expect to hear frequently during the public impeaching hearings. Generally, the memo states, the transcript of Trump's July 25 call with Ukrainian President Volodymyr Zelensky doesn't show a culpable "state of mind" on Trump's part.

Specifically, the GOP memo argues that Trump's call "shows no conditionality or evidence of pressure," says Trump and Zelensky both denied that Trump pressured him during the call, claims the Ukrainian government didn't know Trump was withholding aid when Trump asked Zelensky to investigate the Bidens, and point out that Trump released the aid on Sept. 11 without any public announcement of an investigation he was seeking.

"Whatever you may think of the president or the case that he tried to extort Ukraine's president for political gain, there's a lot in these talking points which are just not true," Anderson Cooper said on CNN Tuesday night. For example, many of the arguments are contradicted or undermined by witnesses involved in Ukraine policy, he said, and "as many legal minds have also pointed out, attempted bribery and attempted extortion are still considered crimes." You can watch his entire fact-check below. Peter Weber

The historic first public hearing in the impeachment inquiry into President Trump is about to begin.

The House Intelligence Committee is set to hold this first hearing Wednesday nearly two months after House Speaker Nancy Pelosi (D-Calif.) announced the opening of a formal impeachment inquiry. The hearing will begin at 10 a.m. EST, with the witnesses being William Taylor, the U.S. charge d'affaires in Ukraine, and Deputy Assistant Secretary of State George Kent.

The House is examining whether Trump improperly pressured Ukraine into opening investigations that he thought might help him in the 2020 presidential election, including involving former Vice President Joe Biden. One of Wednesday's witnesses, Taylor, previously testified that it was his "clear understanding" that Trump was conditioning the release of aid to Ukraine on the country committing to the investigations Trump sought.

Witnesses have testified that Trump was specifically looking for Ukrainian President Volodymyr Zelensky to make a public announcement that these investigations were being pursued, and Kent previously told Congress that Trump "wanted nothing less than President Zelensky to go to microphone and say investigations, Biden, and Clinton."

The impeachment hearing can be streamed at 10 a.m. on YouTube via CBS, with coverage beginning an hour earlier. Brendan Morrow

Much of the U.S., from the Great Plains to the East Coast, was hit with record-breaking cold and snowfall on Tuesday. Thirty percent of the continental U.S. is blanketed in snow, according to National Oceanic and Atmospheric Administration estimates. The "arctic outbreak" was expected to reach the upper Texas coast on Wednesday. "The arctic airmass that has settled into the Plains will continue to spread record cold temperatures south and eastward into the Ohio Valley and down into the southern Plains," according to the National Weather Service. By Wednesday, temperatures in an estimated 300 locations will tie or break cold-weather records. Harold Maass

Pete Buttigieg, the mayor of South Bend, Indiana, is the new frontrunner in Monmouth University's poll of Iowa Democratic presidential caucusgoers. In the poll, released Tuesday, Buttigieg got support from 22 percent of likely caucusgoers, jumping 14 percentage points from Monmouth's last poll in August. Former Vice President Joe Biden lost 7 points, falling to second place with 19 percent support, and Sen. Elizabeth Warren (D-Mass.) lost 2 points, coming in at 18 percent. The only other candidate with double-digit support was Sen. Bernie Sanders (I-Vt.), who gained 5 points to 13 percent support. When first and second choices were combined, Buttigieg led Warren 37 percent to 35 percent.

Buttigieg's support increased across all major demographics. At the same time, only 28 percent of likely caucus goers said they are committed to their candidate, and most said they are open to the possibility of switching contenders. Monmouth conducted the poll Nov. 7-11 among 451 likely Democratic caucus goers; its margin of sampling error is ±4.6 percentage points. Peter Weber