Russia Ukraine war, page-219928

https://www.cis.org.au/commentary/opinion/the-wests-bid-to-expand-nato-eastwards-was-a-mistake/

“So it was hardly surprising that when the Americans began pushing NATO enlargement in the 1990s, Russian leaders across the board — to include Mikhail Gorbachev and Boris Yeltsin — made it very clear this would be unacceptable.When American leaders dismissed the Kremlin’s loud and persistent complaints, Russian leaders pointed out that US leaders would not tolerate Moscow forming a military alliance with Cuba and Mexico and then planting Russian missiles in those countries. So, why should Russia accept the US doing the equivalent in Ukraine? In effect, the spectre of October 1962 was haunting the Russians, although the roles of the two powers were reversed.
The point was not lost on William Burns, the present CIA director, who was the US ambassador to Russia at the time of the 2008 Bucharest NATO summit, when the alliance announced that Ukraine would become a member. Back then, he wrote a memo to secretary of state Condoleezza Rice: “Ukrainian entry into NATO is the brightest of all red lines for the Russian elite, not just Putin”.Burns elaborated: “In more than two and a half years of conversations with key Russian players, from knuckle-draggers in the dark recesses of the Kremlin to Putin’s sharpest liberal critics, I have yet to find anyone who views Ukraine in NATO as anything other than a direct challenge to Russian interests. [NATO] would be seen … as throwing down the strategic gauntlet. Today’s Russia will respond. Russian-Ukrainian relations will go into a deep freeze… It will create fertile soil for Russian meddling in Crimea and eastern Ukraine”