You could start with huge amounts of military hardware. Enough so that the Ukrainians could inflict heavy damage to any invader. Send in some Marines to train the Ukrainians if they need help raising a substantial army. Encourage them to raise a militia so that every male over the age of 18 and under 60 is armed and ready to fight. Give them RPGs, SAMs, whatever they need to inflict a lot of damage on Russian invaders.
Then, go gangbusters on oil and natural gas production, and reserve a huge chunk for Europe and Ukraine. Work to bring the price of energy down by 25 percent or more. That will hit Russia where it hurts.
Then, resume missile defense operations in eastern Europe.
Then, position shiploads of equipment in Germany, Poland and our bases in the Persian gulf, making it clear that we can move quickly if necessary.
We don't have to fight, or threaten WW3, we just have to give the Ukrainians the ability to fight, and we need to inflict economic damage on the Russians. Obama is not doing anything to deter the Russians, nothing at all. Why wouldn't they take the rest of Ukraine?
KGB Putin is a psychotic mass murderer and war criminal and the world’s biggest terrorist.
Thugs are waiting with baited breath. They know we might fight the first guy but probably not the third. Each goon, each monster, each thug wants to be third.
The United States waits - sobbing - with blood running down her legs...