[Goose]

The Soviet Union under Gorbachev was not a democracy.

I was thinking of the US involvement in Afghanistan and the tendency for American public opinion to turn negative on any war the longer it goes on.  But the Soviet involvement in Afghanistan is an interesting case.  What did drive Soviet withdrawal, after 10 years?

The Soviet withdrawal from Afghanistan was triggered by the same thing that all successful insurgencies rely upon. As long as the insurgents refuse to quit, the controlling power must continue to spend blood and treasure to suppress them. Eventually the controlling power realizes that this process will never end. They then evaluate whether it is worth it to continue and decide it is not. Worked for the US against the UK back in the day too. As long as the controlling power has a plausible strategy to win, they will probably keep fighting. When they no longer have such a strategy, they (wisely) quit. Sometimes the strategy exists but it is just too politically hard to do and/or morally unacceptable. Same result.

[Goose]

The Soviet Union under Gorbachev was not a democracy.

I was thinking of the US involvement in Afghanistan and the tendency for American public opinion to turn negative on any war the longer it goes on.  But the Soviet involvement in Afghanistan is an interesting case.  What did drive Soviet withdrawal, after 10 years?

The Soviet withdrawal from Afghanistan was triggered by the same thing that all successful insurgencies rely upon. As long as the insurgents refuse to quit, the controlling power must continue to spend blood and treasure to suppress them. Eventually the controlling power realizes that this process will never end. They then evaluate whether it is worth it to continue and decide it is not. Worked for the US against the UK back in the day too. As long as the controlling power has a plausible strategy to win, they will probably keep fighting. When they no longer have such a strategy, they (wisely) quit. Sometimes the strategy exists but it is just too politically hard to do and/or morally unacceptable. Same result.