Pres. Trump opened 2020 with a bombshell announcement: the assassination of Iranian Maj. Gen. Qassem Soleimani. (CNN)

Soleimani, the head of Iran's military force, was killed in a targeted, US-ordered airstrike in Baghdad on Thur. (CNN)

Iran has vowed "severe revenge" in response to Soleimani's death. Six people were killed in the airstrike, per the WaPo.

Democratic members of Congress have called Trump's actions a "declaration of war" against Iran.

And, it's not just Iran: On Sun., Iraq's parliament voted to expel US forces, ending anti-ISIS cooperation efforts. (AP)

In response, Trump said Sun. that he was considering putting "very big sanctions on Iraq." (CNN)

And, over the weekend, Trump tweeted that he would attack 52 Iranian cultural sites in retaliation—a war crime. (CNN)

Congress is now scrambling to curb Trump's actions. Several Democrats have already filed legislation. (AP)

Virginia Sen. Tim Kaine introduced a privileged war powers resolution, forcing a debate and vote on action against Iran.

Speaker Nancy Pelosi said Sun. that the House will vote on its own war powers resolution aimed at limiting Trump's powers.

The House vote will take place this week. Here's what lawmakers had to say about Trump's actions in Iran.

Here's Rep. Elissa Slotkin, a former CIA analyst:

People from both sides of the aisle seemed to agree that Qassem Soleimani was a "bad guy." Here's Sen. Amy Klobuchar:

The US Embassy in Iraq has already urged American citizens in Iraq to "depart Iraq immediately."

Mayor Pete Buttigieg: "This is going to have consequences...American credibility is unusually low."

Sen. Mitch McConnell: "We are all Americans first and we are all in this together."

Sen. Elizabeth Warren: "We know...Trump is very upset about this upcoming impeachment trial. But look what he's doing now."

Slotkin, who worked under Bush and Obama, said for both presidents, on Soleimani, the "ends didn’t justify the means."

"Endless war" was also referenced by many Democrats.

Rep. Adam Schiff: "Is this going to increase or decrease the risk of war?"

On Mon., Schiff told the Washington Post that he would be calling for open hearings on Iran in Congress.

Sen. Elizabeth Warren: "Why does he pick now to take this highly inflammatory...action that moves us closer to war?"

Sen. Amy Klobuchar: "I was afraid of the escalation of Donald Trump. Trace this back when he got us out of [the JCPOA]."