In the latest development in a complicated fight that has pitted Holocaust survivors and heirs against a bureaucratic and legal tangle of governments, museums and collectors across the globe, lawmakers are considering a bill to ease the repatriation of art taken by the Nazis and their allies.
The Senate bill would primarily loosen the statute of limitations to allow claims made within six years of when victims or their families find looted art and prove their right to it. The bill was drafted to respond to previous cases in which, its proponents say, claims were decided based on legal technicalities, not the merits.
“It is our moral duty to help those survivors and their families achieve what justice can be found,” said Senator Charles E. Schumer, Democrat of New York and a co-sponsor of the bill.
At a hearing on Tuesday, Ronald S. Lauder, the president of the World Jewish Congress, told a panel of senators that the pain inflicted by the Nazis was worsened by the participation of so many in an art theft he called “probably the greatest in history.”
“This was the dirty secret of the postwar art world, and people who should have known better were part of it,” Mr. Lauder said.
Senator Richard Blumenthal of Connecticut, a Democrat and co-sponsor of the bill, said that museums had dodged their obligations to victims.
“They have indirectly aided and abetted the thuggery of the Nazis, who were completely amoral,” Mr. Blumenthal said. “But these institutions have made a pretense of observing the rules of morality.”
Offering her star power to the cause was Helen Mirren, the Academy Award-winning actress who appeared last year in “Woman in Gold,” a film that told the story of one woman’s fight to recover her family’s looted artwork. She told lawmakers that art restitution had “little to do with potential financial gains.”
“Art restitution is about preserving the fundamental human condition,” she said. “It gives Jewish people — and other victims of the Nazi terror — the opportunity to reclaim their history, their culture, their memories and, most importantly, their families.”
In the film, Ms. Mirren portrayed Maria Altmann, the niece of the subject of Gustav Klimt’s “Adele Bloch-Bauer I,” who took back the painting from the Austrian government.
But Ms. Altmann’s story is the exception. The Conference on Jewish Material Claims Against Germany and the World Jewish Restitution Organization revealed in a 2014 report that most countries had fallen far short of their promises to help victims and their families recover their artwork.
In 1998, 44 countries signed the Washington Conference Principles on Nazi-Confiscated Art, an agreement calling for an expeditious, “just and fair solution” for victims of Nazi persecution.
But the treaty lacked the force of law, necessitating a bill like the one now before the Senate Judiciary Committee.
The legislation is riding on an unlikely alliance between Senator Ted Cruz, the combative Texas Republican who dropped out of the presidential race last month, and Mr. Schumer, a top Democrat who has been one of Mr. Cruz’s most ardent opponents on issues like immigration reform. With Senator John Cornyn of Texas, the No. 2 Republican, and Mr. Blumenthal, they revived the effort.
Some legislators questioned whether the bill would override states’ rights to set their own laws regarding statutes of limitations, hinting at potential obstacles to its becoming law.
Mr. Cruz said the Senate bill would “help ensure that claims for the restitution of Nazi-looted art are adjudicated based on the facts and merits, and are not short-circuited by technical or nonmerits defenses that often work to the disadvantage of Holocaust victims and their families.”
Later on Tuesday, the House voted on a resolution pressing Germany to keep its financial commitment to the well-being of Holocaust victims in their final years.
Mr. Lauder said the art legislation took great strides toward righting a wrong that has defied an easy solution.
“I wish this legislation had happened 10 or 20 years ago, but the fact is that it’s happened, it’s going to have a major effect on the future,” he said. “And many works of art — I use the expression ‘the final prisoners of World War II’ — will finally find their rightful owners.”