Not well enough to justify the 2003 war.
(amongst other things, there is a high chance Iraq would end up in a similar place today without it)
It is insane and or dishonest to claim that Saddam Hussein would have fallen when Bashar Al Assad (who looks like a hippy next to Saddam) clung on. Oppose it or don’t, but don’t pretend this is true.
Assad’s regime is a shell of its former self, is more beholden to Iran and Russia than ever, and doesn’t even control all of Syria.
And Russia did have a chance to help Saddam when it “came to it”—between 9/11 and the US-led invasion. Why didn’t they?