No, the mistake was not doing more to prevent the Iranian revolution or at they very least ensuring that Khomeini did not take over. If the Iranian Revolution never happened , there likely is a two state solution by now and peace in the middle east.
Also no Iranian Revolution means:
- Saddam likely never invades Iran or tries to later create and empire in the Gulf as Iran would be a major counterweight to it
- We are not as reliant on Saudi Arabia for oil as we are
- We do not need to rely on Pakistan as much to supply the Mujahedeen against the USSR meaning Pakistan does not get the influence they have over Pakistan which means the Tailban may never take over.
The Iranian Revolution was the most disastrous thing to happen in the middle east in the past century and was basically for Islamists what the Russian Revolution was to Communism.
Reverse back to the 1950s and not assassinate Iran democratic leader in place of a brutal dictatorship who supported American interests.