Between 1990 and 1991, Mikhail Gorbachev attempted to recreate the USSR into a democratic and less-centralized confederation. Communism would be abandoned and a multi-party democracy system would be introduced. The New Union Treaty would have made this possible, but the 1991 coup prevented all of this from happening. With the sudden declarations of independence and the failing economy, the USSR collapsed.
But what would happen if this treaty was signed? What if the USSR changed into a democratic country? Would it last long or would it inevitably collapse?
A lot would depend on the Co-operation between the Union center and the Various republics in general and the relationship between the Russian Federation and the Union government. Because let us be clear, the new USSR would be de facto and de jure a Russian dominated project. A lot of remaining republics would be uncomfortable with that Idea and a lot would depend on how Moscow deals with it's reduced influence.
Another question is would all the republics stick around? Georgia, Azerbaijan, Armenia, Latvia, Lithuania and Estonia would surely not opt to be a part of the new Union. Central Asia would happily join the new political Union.
The success or failure would depend of the relationship between Minsk, Moscow and Kiev, the political leaders of these countries would need commit politically to the new union project. This would mean Russian leadership would have to stop acting unilaterally, share sovereignty with its brotherly Slavic countries in actuality not just in slogan, commit to a program of transition to Markets and capitalism (I think a French style Dirigisme is prefect for the three countries), a common program and policy on participation in global trade and investment, a common defense program, common Fiscal and monetary policy, commitment to build democracy is crucial else you might end up a single republic building political power vis a vis other republics and of course a common foreign policy.....like would the Soviet Union still remain a member of the UN, how would Ukraine and Belarus co-ordinate with the union's foreign policy since they were members of the UN, would Russian foreign ministry take over most of the Union's function? What about the Central Asian republics? would they become UN members.
I think the best outcome amongst the three, would be is if Russian leadership actually acknowledge the existence of Ukraine and Belarus as a separate and Independent nation and let it develop its own relationship with rest of the world, while co-operating in spheres of common interests which they have a lot of and those countries remaining committed to the political, social and economic project of the union. If Russia does this....I do not think either of those nations would feel Russian Hegemony over their countries as an imposition which it is right now and who knows some sections of the society in those two countries might start to identify the interest of their country with that of the Russian state, once the chaos settles down and economic prosperity returns
The Union's relationship with central Asian countries is quite easy, since the Union's three republics can easily dominate them in all spheres the relationship between the central Asian republics and the Russia/Union would be one of client and Patron relationship. Russia can use the resources of Central Asia to dominate economically Belarus and Ukraine and use Ukraine and Belarus's human capital to extract resources of central Asia. Consider this as France Afrique but on steroids.
Once Russians establish the terms of relationship with the remaining republics and set it's house in order, how would they establish relationship with the republics that have left. Armenia would rejoin the Union given the hostile neighborhood, Georgia will not rejoin but would enter into series of treaties that would bind it to the Union, economically and militarily so no NATO membership, relationship with Azerbaijan would be cold but Azeris would not do anything to antagonize the Russians but they would not be happy being under the jackboot of Russian domination.
The only countries that remain are the Baltic republics and Moldova. Those countries would be very complicated and the west would think a billion times before admitting them into NATO membership as far as Baltics are concerned, now as far as Moldova is concerned ...... I am at a loss here, what would the Russians do?