Regime change in Iran would lead to an immediate stabilized democracy.

The finding

What the evidence shows

There's a real argument behind this, that removing an authoritarian government could open the door to a more democratic one. But the actual record of externally driven regime change contradicts the 'immediate' and 'stabilized' part specifically: Iraq and Libya both saw a dictator toppled followed by years of insurgency, civil war, or state collapse rather than quick, stable democracies. Analysts across the political spectrum point to that same pattern as the reason regime change rarely delivers what its supporters promise.