By 2021, all the ways in which Putin tried to regain control over Ukraine – short of a full-scale invasion – had failed. Putin failed to get Ukraine to join Russia’s Eurasian Economic Union in the 2000s and failed to get pro-Kremlin leaders in charge of the Ukrainian government in 2004.[35] Putin failed to establish full control over Ukraine even when Yanukovych was in power.[36] Putin was able to solidify some of his territorial gains in Ukraine through the Minsk II Accords that froze the frontlines in Donbas, but he was unable to exploit those gains to achieve his full desired aims.
Putin tried to coerce Ukrainian President Petro Poroshenko (2014-2019) and later Ukrainian President Volodymyr Zelensky (2019-present) to legitimize the Russia-created illegal DNR and LNR, and Russia’s illegal occupation of Crimea in accord with Ukraine’s Minsk II commitments despite the fact that Russia and the proxies it created had not met their commitments.[37] These efforts, if successful, would have legitimized the principle of Russian military intervention in Ukraine and secured for Russia a permanent lever of influence over Ukraine’s politics. (ISW documented this deliberate Kremlin effort in detail in 2019).[38] Putin failed at that too.[39]
He ran out of options in 2021 so it was down to an invasion