Sens. Tim Kaine (D-Va.), Chris Murphy (D-Conn.) and Rep. Ro Khanna (D-Calif.) are among the Democrats criticizing the Biden administration for Thursday night's airstrike against facilities in Syria linked to an Iran-backed militia group, demanding that Congress immediately be briefed on the matter.

Why it matters: The strikes, which the Pentagon and National Security Council say were a response to threats against U.S. forces in the region, constitute the Biden administration's first overt military action.

What they're saying:

• Kaine: "Offensive military action without congressional approval is not constitutional absent extraordinary circumstances. Congress must be fully briefed on this matter expeditiously."
• Murphy: "Congress should hold this administration to the same standard it did prior administrations, and require clear legal justifications for military action, especially inside theaters like Syria, where Congress has not explicitly authorized any American military action."
• Khanna: "We cannot stand up for Congressional authorization before military strikes only when there is a Republican president. The administration should have sought Congressional authorization here. We need to work to extricate from the Middle East, not escalate."

The other side: The Pentagon said in a statement Thursday that the strike was carried out "in response to recent attacks against American and Coalition personnel in Iraq," and was intended to "de-escalate the overall situation in both eastern Syria and Iraq."

• A National Security Council spokesperson said the Pentagon pre-notified Congress, and that the administration is continuing to brief the Hill at the member and staff level.
• "As a matter of domestic law, the president took this action pursuant to his Article II authority to defend U.S. personnel," the spokesperson said.

The big picture: All three Democrats have been outspoken against past presidents' attempts to conduct offensive military operations without congressional approval.

• Kaine has led the charge in the Senate to repeal the 2002 Authorization for the Use of Military Force (AUMF) against Iraq and to replace the 2001 AUMF — which has been cited repeatedly by presidents to justify U.S. military action all over the world — with a narrower authorization.
• Kaine and Khanna also introduced resolutions passed by Congress in 2020 that would have required former President Trump to get congressional approval before taking military action against Iran, but it was vetoed by the president.