Why Putin can't let go of Ukraine

Russian President Vladimir Putin observes naval drills from the guided-missile cruiser Marshal Ustinov in the Crimean port of Sevastopol, Crimea, January 9, 2020.Sputnik/Alexei Druzhinin/Kremlin via REUTERS
Russian President Vladimir Putin has again ramped up pressure on Ukraine.
Putin's moves harken back to Cold War struggles and serve Russia's goal of asserting itself as a global power.
Underpinning Putin's efforts is a historical view of Ukraine as a part of Russia's greater empire.
Ukraine i