Compare: Russian invaded Ukraine, U.S. invaded Iraq

There are similarities and differences.

A difference: A Ukraine bristling with missiles (a real possibility given the U.S. support for Ukraine)

would have been a real threat to Russia.

OTOH, that Iraq would have ever been a real threat to the U.S. never seemed likely, except to the neocons.

A similarity:

Who has been advocating that the U.S. get involved in both those conflicts?

The neocons.

Of course they pushed for the U.S. to invade Iraq.

And now they are arguing that the U.S. take steps which have an uncomfortably high probability of leading to a war between the U.S. and Russia.

Some examples:

For a broad look at neocons support for U.S. involvement in the Russia/Ukraine conflict, see

https://responsiblestatecraft.org/neoconservative-ukraine/

by Katrina vanden Heuvel

For Eliot Cohen, read

https://www.foreignaffairs.com/ukraine/theory-victory-ukraine

Elliott Abrams gave a two hour video briefing (covering a variety of topics, including Ukraine), just two weeks after the invasion started, here:

https://youtu.be/R3R-hv2oCZU