Foreign states have been wary of loaning artworks to U.S. museums for exhibitions ever since the 2007 Malevich case.

Heirs of artist Kazimir Malevich had sued the City of Amsterdam over the loan of his artwork to U.S. museums. The heirs contended the artwork was illegally acquired post-WWII and Amsterdam was benefitting from the loan. A federal court in DC allowed that the City of Amsterdam conducted 'commercial activity' with the loan. Entanglements ensued that stymied some loans from other countries to American museums. 

A new law passed last month comes with the intention of easing international loans to U.S. museums. The so-called Art Museum Amendment includes two exceptions; one allows 'Nazi-Era Claims' and the other is more broad, if not unclear.

Ingrid Wuerth writes in Lawfare Blog:

A little-noticed bill to amend the Foreign Sovereign Immunities Act (“FSIA”) passed both houses of Congress in December and was signed into law by President Obama on Dec. 16, 2016.   The bill (“ The Foreign Cultural Exchange Jurisdictional Immunity Clarification Act (FCEJCA)” or “Art Museum Amendment”) narrows the expropriation exception in the FSIA to provide greater immunity for foreign states which send works of art to the United States for temporary exhibit.  Unfortunately, the FCEJA may ultimately be more harmful than helpful to foreign states.