Democratic lawmakers speaking at the Monday evening gala of J Street’s Washington conference argued that the joint U.S.-Israel operation that killed many top Iranian leaders, including Supreme Leader Ayatollah Ali Khamenei, would ultimately make Iranians, Israelis and the United States less safe.

“I do not believe that the United States or Israel should be leading a regime change operation in Iran. It will not bring safety or security to the people of Iran, to the region or to the United States, and it’s important that all of us here in this room continue to stand up and say that,” Rep. Sara Jacobs (D-CA) said. “We’ve lived through this before. Regime change often backfires. It creates power vacuums, leads to even harder-line leaders and civil wars and failed states.”

She also argued the U.S. set Iran on the path toward the current regime’s leadership by backing the 1953 overthrow of the Mossadegh government in Iran.

Expressing her support for the war powers resolution vote taking place in the House later this week, Jacobs said, “We can’t be equivocal, that we have to say strongly and clearly that what is happening is not OK, and it is not making Jews in Israel or here in the United States any safer.”

Sen. Adam Schiff (D-CA) said that he does not mourn Khamenei nor the other Iranian leaders who have been killed, “but we have not just cut off the head of the snake. We have almost certainly kicked up a hornet’s nest, one with remaining capabilities and appetite for revenge. Now we ask, what comes next?”

He said that the administration entered into the operation without any clear plan to effect the regime change it appears to desire, nor how to protect and support the Iranian civilians the Trump administration has urged to rise up against the regime.

Sen. Tim Kaine (D-VA), the lead sponsor of the war powers resolution set for a vote this week in the Senate, made the case for his legislation, saying, “That vote in front of the American people is a way of clarifying what’s at stake and deciding if the mission is so important that we should risk our own kids’ lives.”

Former House Speaker Nancy Pelosi (D-CA) said that the “vote is not about whether we should go in or not. The vote is that you cannot go in unless Congress gives you the [authority],” framing the vote as an affirmation of Congress’ constitutional power to declare war.

Kaine emphasized that J Street’s influence within the Democratic Party has grown, saying that “virtually all” Democratic senators now seek the group’s endorsement.

Throughout the Purim-themed evening, speakers repeatedly drew comparisons between Trump, Israeli Prime Minister Benjamin Netanyahu and members of Trump’s administration and Haman, the villain of the Purim story.

“This is a moment not unlike the scenes that gave us the story of Purim: a hedonistic king less interested in justice than in his own pride and pleasure. A ruler flanked by evil advisors, his toxic grip on power unleashing danger and violence,” Schiff said. “It is all too reminiscent of the plots against the Jews driven by him.”

And in an unusual moment, Kaine capped off his remarks with a sing-along rendition of Woody Guthrie’s “This Land is Your Land,” playing his harmonica through the choruses.