“It is in the United States’ interest, especially from a national security perspective, that Ukraine stop Putin.”
An easy claim to make, impossible to substantiate.
If it were true, then it would make sense for the US to go to war in Ukraine against Russia.
But it’s not true.
No. Ukraine is not a US ally and sending US troops would be a mistake. This is not an all or nothing proposition. Reagan defeated the Soviet Union without ever going to war against them.