Permanent. The term is 95 years now, unless Congress changes the law. And reducing it would be very difficult legally, with copyright holders suing for their theoretical losses if Congress "deprives" them of 20 years of protection that they now consider their property.
I don't know if those suits would succeed. If Congress gives someone a benefit and then gets rid of it, then you can't sue the government to force them to keep giving it to you.
You can, and it'll go through the federal courts. Your case might be quickly dismissed, or it might eventually cause a Consitution question to the Supreme Court. Or not.
