Could they be goading the US into doing something stupid or encouraging Ukraine or its thugs to do something stupid and then they'll be justified to take a corridor in eastern Ukraine to connect Crimea to Russia?
It is wise to examine this tactic and consider it among all the others.
It is also wise to consider the exact opposite situation, that Obama is tactically trying to goad Russia (Putin) into doing something stupid so the world will see Obama's actions as justified.