President Biden: "The idea the United States will unilaterally use force to confront Russia invading Ukraine is not in the cards right now."

"I was very straightforward. There were no minced words. It was polite, but I made it very clear. If in fact, [Putin] invades Ukraine, there will be severe consequences, economic consequences like none he's ever seen or ever have been seen."

The threat of sanctions is meant to deter a full-blown Russian invasion of Ukraine. But history shows that sanctions are no more of a deterrent to Putin than a speed bump to a monster truck. Just ask the good folks of occupied Crimea. Or occupied Georgia.

Adversaries have learned to live with sanctions. Just ask the ayatollah.

Putin had demanded an end to NATO enlargement and a promise from the allies to stay away from Moscow’s near abroad. Reports are Biden did not and won’t agree to that. That gives Putin moral justification to attack Ukraine or any nearby country that will threaten Moscow with NATO weapons.

However, Biden can’t say the U.S. will fight to defend Ukraine. Ukraine is not a treaty ally. What’s more the U.S. doesn’t have to fight for Ukraine. Ukrainians can do that. There are 44 million of them. If Putin attacks, he will have a fight on his hands. The Russians would have to strike in winter, against determined defenders.