Between 2007, and February 24, 2022, former presidents George W. Bush, Barack Obama, Donald Trump and Joe Biden floated NATO membership to Ukraine. This was in violation of George H.W. Bush’s 1991 promise not to expand NATO eastward toward Russia.
Sensible diplomats and historians scolded the US that such a move east was a red line of provocation that would inevitably result in military Russian pushback. They compared it with JFK’s willingness to start nuclear war with Russia to prevent installation of Russian missiles just 90 miles from the US in Cuba.