canofhumdingers said:

I'm not entirely sure that's true... If it's on the National Film Registry I think they might be allowed to duplicate/preserve it without the copyright owner's permission. But don't quote me on that as I'm not 100% positive.

Of course, if they can legally preserve/duplicate it, they still wouldn't be allowed to make copies for distribution.

I do know for certain that they are legally allowed to screen anything in their collection publicly, copyright or not, so long as it's screened for free at the LoC's theater facilities.

I can see it now. A newly organized movement begins to preserve and release the UOT. The internet is abuzz for months. Thousands of SW fans head to DC to attend a planned screening of SW and ESB in their unaltered glory by the LoC. People like Gary Kurtz, Paul Hirsch, and Lawrence Kasdan attend the screening to show their support. The event sends ripples throughout the film community. It's a huge hit. Pressure on LFL to properly restore and release the UOT increases. After months and maybe a year or more, LFL consents and the fans get what they've wanted for so long. The excitement and happiness mirror the celebration on Endor at the end of ROTJ. The internet arguments dwindle. Everyone is happy with his/her preferred versions of SW. New generations experience the OT as their ancestors did in the 70s and 80s. Lucas admits he was wrong to change the movies repeatedly. Over time the special editions become a blip in the rich history of SW. The UOT lives on in all its glory!

The UOT was dead; its body, with a broken neck, swung gently from side to side beneath the timbers of Skywalker Ranch.