The specter of military escalation with Iran will take center stage for lawmakers this week as they return to Capitol Hill for briefings on the Trump administration’s justification for last week’s targeted killing of Iranian Gen. Qassem Soleimani and the House holds a vote on a resolution that would restrict the president’s ability to go to war with Tehran.

Aftereffects from the drone strike on Soleimani, who as the leader of the Islamic Revolutionary Guard Corps’ Quds Force was seen as Iran’s second-most powerful official, continued to build over the weekend. Those repercussions include a vote by the Iraqi parliament to order the expulsion of U.S. military forces, although no deadline was specified; warnings from senior Iranian figures and proxies like Hezbollah leader Hassan Nasrallah that retaliation could take the form of attacks on U.S. military sites; and Tehran’s announcement that it would cease abiding by the 2015 multinational nuclear deal not to enrich uranium.

In response, the Pentagon has ordered a pause in its campaign against Islamic State terrorists, who are attempting to rebuild in Iraq and Syria. The pause is intended to free up resources to focus on protecting deployed coalition troops from retaliatory attacks by Iran and its proxies.

The Defense Department also ordered the deployment of more than 3,000 additional U.S. forces to the Middle East, and President Donald Trump took to Twitter to threaten strikes on 52 important sites inside Iran, including “cultural sites,” if Tehran retaliates for the Soleimani assassination. The targeted destruction of cultural sites is a war crime under international law.

Trump also told reporters Sunday that he could impose “very big sanctions” on Iraq if Baghdad forces the withdrawal of U.S. forces. Up until this month, the administration welcomed popular unrest in Iraq against the growing influence of Iranian-backed militias and political parties, which many Iraqis feared threatened their country’s sovereignty.

Amid this flurry of news developments, lawmakers are pushing to get more information from the administration regarding the intelligence about “imminent” threats to U.S. lives, which officials say justified the killing of Soleimani.

Both the House and Senate will receive all-hands briefings Wednesday afternoon. Briefers are expected to include Secretary of State Mike Pompeo, Defense Secretary Mark Esper, Joint Chiefs of Staff Chairman Gen. Mark Milley and CIA Director Gina Haspel.

War Powers vote announced

Pursuant to the 1973 War Powers Act, the White House on Saturday officially notified Congress in a classified document of the drone strike on Soleimani. The law requires Congress to be notified within 48 hours of the initiation of any hostilities not covered by a declaration of war or congressional military authorization.

Democrats criticized the secret notification, arguing it was important for Americans and their congressional representatives to debate openly the details of policies that could escalate to a full-blown war with Iran. And others, particularly those in the anti-war community with memories of how the Bush administration manipulated U.S. intelligence findings to justify the 2003 invasion of Iraq – – saw in the Trump administration’s reticence to disclose the intelligence as one more reason to be skeptical.

[Political fallout from Soleimani could be biggest for Senate]

“It is critical that national security matters of such import be shared with the American people in a timely manner,” said Senate Minority Leader Charles E. Schumer of New York and Senate Foreign Relations ranking member Bob Menendez of New Jersey in a Monday letter to Trump calling on him to declassify his War Powers Act notification. “An entirely classified notification is simply not appropriate in a democratic society, and there appears to be no legitimate justification for classifying this notification.”

House Speaker Nancy Pelosi said the House would vote later this week on a privileged resolution soon to be introduced under the War Powers Act by Rep. Elissa Slotkin, D-Mich., that would require the U.S. military to “cease” any military hostilities toward Iran within 30 days of enactment if Congress does not pass a new authorization for the use of military force.

“Last week, the Trump administration conducted a provocative and disproportionate military airstrike targeting high-level Iranian military officials,” the speaker said in a Sunday letter to her caucus. “This action endangered our service members, diplomats and others by risking a serious escalation of tensions with Iran.”

Slotkin, who served three tours in Iraq as a CIA analyst focusing on Iranian-backed militias before holding senior policy positions in the Pentagon, noted that both the Bush and Obama administrations considered but ultimately rejected killing Soleimani, who is responsible for the deaths of hundreds of U.S. service members, after they concluded such a strike carried too great a risk of resulting in a protracted conflict with Iran.

“The Iranian government has vowed to retaliate and avenge Soleimani’s death, and could do so in any number of ways: against our diplomats and service members or high-ranking military officers, against our allies and partners in the region, or through targeted attacks in the Western world,” Slotkin said in a Friday statement. “It is critical that the administration has thought out the moves and counter-moves this attack will precipitate.”

Slotkin’s resolution is similar to a measure introduced on Friday by Sen. Tim Kaine under the War Powers Act. While the Virginia Democrat’s privileged resolution is entitled to a floor vote, Senate passage is uncertain.

Last summer, Kaine secured a vote on a bipartisan amendment he introduced to the Senate’s version of the yearly defense policy bill. While the Senate voted 50-40 in favor of the amendment, which would have required congressional approval before the U.S. entered a conflict with Iran, it was not adopted as it failed to meet a required 60-vote threshold.

And so even though the House, including 27 Republicans, also voted last year to limit Trump’s scope of action toward Iran, that language was deleted by Republican leaders during final conference negotiations for the fiscal 2020 defense authorization measure.

“This action does risk further military escalation, and given those risks, Congress must not be side-lined,” Sen. Susan Collins, R-Maine, said in a statement after Soleimani’s assassination. “The administration must quickly brief Congress on all available intelligence and its strategy to protect American citizens and service members against Iran.”

Still, the state of play is much different this year for Republicans, primarily as it is an election year, and many GOP members are loath to criticize their party’s standard-bearer.

At the same time, some small number of Republicans such as Collins may look for ways to limit the potential for all-out war with Iran, which is generally unpopular with the American public. In fact, Republicans are largely seen to have lost both the House and the Senate in the 2006 midterms over voter dissatisfaction with Bush’s handling of the Iraq war.