In 2020, the end of the Soviet Union seems more or less inevitable. However, how much of that is reality and how much of that is hindsight bias? What were American officials saying or thinking about the future of the Soviet Union in its last year? Were they seeing an eventual collapse? Or was there faith in the policies of Gorbachev to keep the USSR going indefinitely into the future?
Interestingly, the CIA actually laid out a number pf possible scenarios for President Bush in late June 1991, concerning the turn of events in the USSR:
Scenario one saw the republics becoming independent, but through violent fragmentation of the Union.
Two other scenarios were that the USSR would, in effect, muddle through somehow. Another was that hard liners would mount a coup against Gorbachev, and basically turn back the clock (and thereby preserve) the USSR.
A final scenario was called a "system change", whereby the Baltic States, Caucasian Republics and Moldova (at the time, the most nationalist republics that had actually elected non-communist republican governments), would be allowed to secede, but the remaining republics would continue in a Union.
The fact is that elements of basically all of these scenarios played out, but not as the CIA projected they would. There indeed was a coup attempt against Gorbachev on August 19, but it failed, and actually hastened the disintegration of Soviet institutions and the communist party. The Union did completely fragment, but not violently (or not on the scale that the CIA or President Bush feared, which was something like a Russian Civil War 2 with nukes). A few of the former Soviet Socialist Republics moved as far from Russian influence as possible, while others remained closer to Moscow, but the Commonwealth of Independent States, Union State and Eurasian Economic Union notwithstanding, there really hasn't been a union approaching the USSR between former Soviet republics.
Just to give a sense of where things were in the USSR in June 1991, it was clear that the country was rapidly approaching a crossroads...but not really clear where that would lead it. By the end of 1989 the former Soviet satellites of Eastern Europe had been overthrown or were negotiating a handover of power to other parties, and Bush and Gorbachev met in Malta in December to officially declare an end of the Cold War. Gorbachev, who had already been pushing for economic restructuring ( perestroika) and greater political transparency (glasnost), had already held semi-free legislative elections in 1989, and in 1990 pushed ahead with more constitutional reforms, creating the office of Soviet president for himself, while also repealing the constitutional article proclaiming the Communist Party the sole legal party and revolutionary vanguard for the country.
Most republics had followed Gorbachev's lead and established republican presidencies, with Boris Yeltsin (a fierce populist and political antagonist of Gorbachev's) being elected Russian president in June 1990. Later in that year the Republics began declaring "sovereignty" (declaring ownership over natural resources within their borders and claiming Soviet laws would only be enforced with their assent), starting a so-called "War of Laws" with the Soviet center. There was then a tack on Gorbachev's part towards the hard liners (a number of major reformers left his government, he dithered on supporting further reforms, and began to be advised increasingly by the security forces, which cracked down on dissident movements, such as at the Vilnius TV tower in Lithuania and in Riga, Latvia in January 1991.
As the situation (and society and economy) became increasingly chaotic, Gorbachev attempted to replace the constitutional order underpinned by the 1922 Union treaty with a new treaty establishing a federal order between the republics and center, holding a referendum in March 1991 that broadly supported this (although the referendum wasn't even held in the Baltics, Moldova, Armenia or Georgia). A treaty was hashed out at Novo Ogaryovo in the spring, and set to be signed by Gorbachev and the republic heads on August 20 - the coup the day before was specifically to stop this.
So by June 1991 the USSR was clearly in political, economic and social turmoil, and it wasn't incredibly clear to any American analysts or government leaders just how this would resolve. Yeltsin was actually disliked by Bush at this time, who thought Gorbachev was a much more reasonable and professional partner. It wasn't clear (even to Soviet reformers) that greater power to the republics meant an unraveling of Soviet institutions - or an attempt to stymy reforms by empowering hardliners (Russia only got its own republican Communist Party in 1990 and it was noticeably hardline in its stances).
Bush himself visited Gorbachev and the USSR in late July - early August 1991, and gave a rather infamous speech to the Ukrainian legislature in Kiev (dubbed the "Chicken Kiev") speech, warning against rash moves towards nationalism and independence and citing the then-unfolding violence in Yugoslavia as a warning of what might happen. It was clear that something was coming - but it was unclear just what, or who would gain in a political struggle, or how bloody it would be. No one (not even the participants!) even in the late spring of 1991 foresaw the events leading to that December and beyond.