Putin's Ukraine assault confounds Biden strategy

Russian President Vladimir Putin addresses the nation. On Thursday, he authorized what he called a "special military operation" into the Donbass region of eastern Ukraine, marking a new high in post-Cold War tensions. (Alexei Nikolsky/Sputnik/Kremlin Pool Photo via AP)

He threatened to impose the harshest sanctions ever on Russia. He worked to galvanize US allies into a united front. He supplied Ukraine with more weapons than any American president before him. And he beefed up US forces on NATO's eastern flank as reassurance of his commitment.

Despite US President Joe Biden's efforts to head off a Russian attack against Ukraine, President Vladimir Putin was undeterred.