Marc Masurovsky  has helped me out, by going into some of the issues with the Foreign Cultural Exchange Jurisdictional Immunity Clarification Act .
The bill has now been introduced in the Senate as S. 2212. The worry is, that many of the successful cases that have been brought in the US in recent years, to secure the return of looted cultural property would no longer be possible. For those of you in the USA, the Senators supporting the bill are: Dianne Feinstein  and Orrin Hatch . As he points out, Fenstein has many major museums within her community, which includes San Francisco & Los Angeles.
As Marc says “It’s the end of art restitution as we know it.” Supporting such a bill would be a backward step for the country that is currently one of the more forward thinking (well compared to the UK at any rate) in terms of cultural property restitutions & the legal framework that allows them to take place. “After all, once you write a bill that carries with it select exclusions, it implies that you tolerate other forms of looted art to enter the US for display. Hence, the clarification to the Foreign Sovereign Immunity Act should either be all-inclusive or dropped entirely. It is absolutely critical for source countries to express themselves”.
Doubtless, many organisations such as the AAMD  are unlikely to agree with this point of view.
More details of the act can be found in my original post on it .