Even without the Sony Bono's Heirs/Mickey Mouse Protection Act LotR would still be under copyright. Tolkien died in '73 so I believe the copyright in the US would have expired next year (life of the author+50 was the old standard in the US at least). And of course it had no impact on the UK copyright either, which is also now currently life of the author+70 just like it is in the US.This shouldn't even be an issue. All that ancient stuff should be in the public domain.
I blame Sonny Bono.
Which does bring up another question - the rights that the Saul Zaentz company are selling are basically for the next 20 years in the US and UK (which is where I'd think the Middle Earth license would be most lucrative, could be wrong!) - it'll be curious to see how much they go for given the time limit and how the company that buys them intends to make that money back in a timely fashion.