There is nothing wrong with sending U.S. military advisers to Ukraine. But of course they’ll need a base of operations. And that base must be protected. So we’ll have to send in air support and artillery units as well. And infantry units to secure the area around the base.
Oh, wait. I’ve seen this movie before. And it didn’t end so well. I guess it’s not such a good idea after all.
[There is nothing wrong with sending U.S. military advisers to Ukraine. But of course they’ll need a base of operations. And that base must be protected. So we’ll have to send in air support and artillery units as well. And infantry units to secure the area around the base.
Oh, wait. I’ve seen this movie before. And it didn’t end so well. I guess it’s not such a good idea after all.]
https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-15#Soviet_MiG-15s_in_the_Korean_War
https://en.wikipedia.org/wiki/List_of_Korean_War_flying_aces#Soviet_Union
https://www.smithsonianmag.com/smithsonian-institution/seventy-years-ago-soviet-mig-15s-attacked-american-pilots-180977440/
They could just send aircraft the way the Russians did in Vietnam:
https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-17#Vietnam_War
https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-19#Vietnam
https://en.wikipedia.org/wiki/Mikoyan-Gurevich_MiG-21#Vietnam
I’d say the second option comes with fewer complications.