The ruling was specifically focused on foreign works as they relate to the Berne Convention. This international treaty binds signatory nations to the copyright protections provided in countries where the original art was created. It would apply to both US copyright holders to protect their works abroad and foreign copyright holders where their works are used here.
The Wikipedia page on the Berne Convention has some really interesting facts on this treaty and you should read it before voicing opposition to the SCOTUS ruling or claiming "American Exceptionalism" is being run over by a truck. This is not a bad ruling and the 6-2 vote suggests 1 judge appointed by a liberal President agrees with the argument. Ne, if you get into the opinion (link below) you'll find that two conservative appointees dissented while the remaining justices agreed (sans Kagan who recused). The point is that this was hardly a "party line" or ideological divide.
The official opinion here: http://www.supremecourt.gov/opinions/11pdf/10-545.pdf
Some worthy quotations from the Wikipedia page found at: http://en.wikipedia.org/wiki/Berne_Convention_for_the_Protec...
Before the Berne Convention, national copyright laws usually only applied for works created within each country. Consequently, a work published in United Kingdom (UK) by a British national would be covered by copyright there, but could be copied and sold by anyone in France. Likewise, a work published in France by a French national could be copyrighted there, but could be copied and sold by anyone in the UK. Dutch publisher Albertus Willem Sijthoff, who rose to prominence in the trade of translated books, wrote to Queen Wilhelmina of the Netherlands in 1899 in opposition to the convention over concerns that its international restrictions would stifle the country's print industry.
The United States initially refused to become a party to the Convention, since that would have required major changes in its copyright law, particularly with regard to moral rights, removal of the general requirement for registration of copyright works and elimination of mandatory copyright notice. This led to the Universal Copyright Convention in 1952 to accommodate the wishes of the United States. But on March 1, 1989, the U.S. Berne Convention Implementation Act of 1988 was enacted, and the United States Senate ratified the treaty, making the U.S. a party to the Berne Convention, and making the Universal Copyright Convention nearly obsolete.
Editorial. I believe in American exceptionalism on a number of fronts including some trade issues. But, the notion that any individual or group of people from one country can merely disregard the copyrights of and profit from works created in another is ludicrous. I feel bad for the plantiffs -- the orchestra members who brought the suit. They have been treated unfair, not by the SCOTUS, but by a general failure of US enforcement of foreign copyright as provided by the treaty.
Just my $0.02