Oh I completely agree that sanctions are unlikely to change their behavior. But we must realize that a full scale war against Iran in todays environment would not turn out well.
As much of a mistake it was to overthrow other dictators in the Middle East has been, supporting a popular uprising that leads to the overthrow of the Iranian government may be the least bad choice. Sanctions are part of that strategy.
Bombing their nuclear facilities is another path. This would likely occur after Iran attacked one of our ships in the gulf. Big risk here once again.
changing governments to look like us is never a good idea and should avoided. Supporting an uprising can be an avenue, but we blew it when letting down the students revolution early in Obama’s reign.
But a tight ring around Iran, interrupting all travel, shipping, etc. might be considered, which would likely cause an uprising. The American left and EU would go crazy.
Destroying their nuclear capabilities is another possible scenario.
Options are limited.