What other cards to they have to play? The West has been sucking up to Ukraine since the collapse of the USSR, dangling NATO membership and EU goodies in their collective faces, apparently without ever considering the fact that the Russians might not be willing to play along.
It might have even worked if we had a real leader as a President. One the Russians could respect and who would taken steps years ago to prevent the current situation from developing. But we don’t, we didn’t, and the Russians see a perfect opportunity to jerk Kiev back into Moscow’s orbit, so they are taking it.
The US will not (nor should they) get involved in a fight about the Ukraine. We simply do not have a stake big enough to justify intervening. It would be different if Ukraine was an actual NATO member, but they aren’t.
No, but they can do much more short of war. Cut off all trade relations. This time, don’t back off like we did in Berlin back when the Iron Curtain descended. Send tanks and troops into Kiev, Warsaw, and every Eastern European and former Soviet nation willing to take them. Call Putin’s bluff.