[Care_Bear]

Did the Soviet Union collapse because of nationalism in the Baltic. Were the Estonians and Lithuanians pushing for independence after the Eastern European countries left the Warsaw Pact in 1989.

Did Gorbachev sympathize with these movements and abhor violence thus allowing them to leave, and the whole Soviet Union came down like a house of cards?

[Smilin' Dave]

Did the Soviet Union collapse because of nationalism in the Baltic.

If nationalism were a factor in the collapse of the Soviet Union it would have been more than just the prominent example of the Baltic states. Ukranian nationalism for example was a big deal and even after the collapse there were a number of breakaways or threats of same (Chechnya but also a lot of other southern republics played with the idea).

Did Gorbachev sympathize with these movements and abhor violence

I don't think Gorbachev was sympathetic, after all at that stage was still pushing for a new Union, not a dissolution. I do however think it is probably right that he didn't want to use violence when things did go wrong. The standard narrative seems to be that what violence did occur during the independence movements in the Baltics etc. were the acts of local leaders of 'rogue' politicians at the centre.

thus allowing them to leave, and the whole Soviet Union came down like a house of cards?

I don't think nationalism alone explains the collapse, though it did contribute to the speed and manner of it. After all there had been nationalist movements etc. in these places before and generally nothing much came of them. Instead you have to ask yourself why there was a big push to leave the USSR at that particular point in time. Now, part of that would have been the example of the collapse of the Eastern Bloc, but there is also the consideration of the first economic stagnation and then the economic crisis that followed Gorbachev's clumsy reforms. When the old centre looks like a bad long term 'bet' and can't even offer statability, you start to look at what local political actors have to offer.