Together, Mr. Royce, then the chairman of the House Foreign Affairs Committee, and Mr. Engel invited Caesar to testify before the committee in 2014 and wrote the Caesar bill. They did so over the objections of the Obama administration, which had argued that imposing sanctions on Syria would endanger its diplomatic outreach.
“They wanted him to come quietly and leave quietly,” said Muna Jondy, the policy chairwoman of Americans for a Free Syria, a nonprofit advocacy group that helped bring Caesar to the United States and lobbied for the sanctions. “We refused.”
Ignoring the pressure from the White House, lawmakers passed the bill in the House in November 2016 — but continued to run into problems in the Senate. When the Senate finally did pass the bill in early 2018, included in a legislative package of Middle Eastern policy, the House refused to take it up because the package included a provision affirming the right of local and state governments to break ties with companies that boycott or divest from Israel.
Even with the backing of the Trump White House, attempts to pass a stand-alone version of the legislation in the Senate repeatedly failed. When Senator Jim Risch, Republican of Idaho and the chairman of the Foreign Relations Committee, tried to pass the legislation through unanimous consent last December, Senator Rand Paul, Republican of Kentucky, blocked the effort.
“These sanctions will delay — and possibly prevent — the reconstruction of Syria and the beginning of a healing time,” Mr. Paul said. “Now is the time for diplomacy.”
Senator Mitch McConnell, Republican of Kentucky and the majority leader, came out in support of the legislation in October in a Washington Post op-ed article condemning the withdrawal of American forces. His office played a pivotal role in ensuring the legislation was included in this year’s military policy bill, according to activists who lobbied lawmakers to guarantee its passage.
Ms. Jondy, a former member of the Syrian National Movement and the Syrian Constitutional Committee, a group authorized by the United Nations that seeks to reconcile rival sides in Syria’s war, met with Syrian government officials in November in Geneva, in an attempt to draft a new governing document. At that meeting, Ms. Jondy said, it was clear that Syrian officials were nervous about the possible imposition of the Caesar sanctions.
“We know sanctions are hurting,” she said. “We’re going to try to give you more.”