Ukraine is our friend. They have done more in 8 weeks to fight for democracy than the overwhelming number of Americans will do in their entire life. We cannot let Putin have his way. We have to have Ukraine's back, no matter the cost.
I am well aware that seasoned and vastly experienced US experts and professionals have war gamed every option and scenario a multitude of times, concluding that US military engagement is too big a risk to trigger escalation leading to nuclear war. I am also well aware that US/NATO military involvement is exactly what Putin will use to justify his aggression.
On the flipside, nuclear war is a terrible option for Putin and Russia. Also, it appears that the Russian dissidents have lost momentum, whereby the Russian people are largely soaking up their version of Fox News propaganda.
We cannot let Putin extort the West, and carve off what he decides to eat, without consequence. Sanctions are effective ... to a point, but require a long game -- years. My fear is that Ukraine will be inclined to cut a deal with Putin in order to end the bloodshed and suffering.
Strength -- overpowering strength -- is what bullies understand. In the name of responding to the war crimes perpetrated by Russian, NATO/US military power could crush Russian forces in their tracks. Send the Russian troops crawling home, without food or weapons. That is the message to be delivered.