ricecake , 7 hours ago

An all out war is unlikely, since if NATO involvement was going to kick that off it would have done so by now.
The next point of escalation that could start something bigger would be stuff like NATO openly sending troops or actively providing fire support.

US hesitation to allow our hardware to be used for this type of attack is much more to do with the political issues surrounding the war being framed as a proxy war instead of defensive support.
The electorates support for “saving the day” and “superior US hardware helping keep a country free” is high. Support for a protracted and complex proxy war without clear right and wrong sides is exhausting and hits too many Iraq/Afghanistan buttons for people to care.

Asking for and publicly being denied permission to bomb targets adjacent to the capitol does just as well at communicating “we can bomb your capitol” as actually doing it.