What should the U.S. do if Russia invades Ukraine?

Answers seem to be all over the place from both sides of the aisle. I haven’t heard much of a coherent strategy on this situation from anyone. Biden is simultaneously too weak and too hawkish. So what specific actions should the United States take if Russia invades Ukraine?

Remember of course that Russia did invade Ukraine in 2014 and the U.S. did nothing consequential.