Grow up.
The broader parameters have been set by the US/NATO not to step onto Ukrainian soil at any point/supply it with aircraft/set no fly zones etc, thus giving the rare advantage to the enemy (Putin) of knowing that we will remain inactive regardless of whatever depredation he visits upon the population. We should -minimum, and for example- have at least warned him through private channels that if he uses chemical or biological weapons, we will respond militarily. Now, whether you fear that might lead to WWIII or not is irrelevant. In the face of a brutal bully, a stand must be taken, action threatened and followed through with.
Biden's permissive pre-war comments about the comparative acceptability of a 'minor incursion' helped set a confused and unresponsive tone for the invasion and if America is not going to take the boldest possible steps to assist the Ukrainian people, at least Biden could step up the public rhetoric in defense of the values the Ukrainians are fighting for in this conflict, which go beyond their country's sovereignty.