I think also after the Revolution the West instantly became hostile toward the Mullah regime which brought them closer towards the USSR which would've made them a natural ally for us too from that pov at least as it would be a significant anti-West power bloc in that region.
West turned hostile because the Iranians under the Mullah's took hostages in the US embassy for more than a year , something which cost Jimmy Carter his second term as President & saw Reagan win the election.
Russia was initially bound to the west during Yeltsin's presidency before the relationship soured. In any case they were too deeply involved in setting their home in order neglecting foreign affairs.
Prior to that during the Iran Iraq war , believe it or not , everyone from the west to the Gulf Sheikhdoms to the USSR - all of them supported Saddam Hussein's Iraq . Check out the arsenal of Iraq then . It's full of USSR & French weapons & platforms especially their Air Force .
India literally trained 100s of Iraqi pilots then. We had a special relationship with Iraq primarily due to Cold War politics.
Iran would never have supported Pakistan in any conflict with us after the 80s other than maybe at best issuing some token statements
Reasons have been forwarded in my previous post.
while the Shah plied them with military equipment and oil at subsidised rqtes what with both being a part of CENTO.
Mostly due to Nixon & Kissinger leaning on the Shah & other Gulf Sheikhdoms to back Paxtan with material & money since they couldn't do so directly given the Congressional ban on any kind of assistance to both India & Paxtan.
Iirc the Mullah regime also opposed US sanctions on us in the 90s. It was an important part of our foreign policy tight rope walk for a reason with the rhe Gulf sheikhdoms too not having the sort of relationship with us then that they do now.
Agreed. But this opening wasn't as straight forward as people may think it is . Right through the Iran Iraq war , Iranians kept shelling our oil tankers carrying Iraqi oil to India. IIRC we lost the maximum number of tankers of any side in that conflict.
The break through came mostly during ABV's tenure thanks to leg work done by our diplomats there.
Significant changes in world geopolitics enabled this. In the 1990s the world was a different place. Iraq was neutered in Gulf War -1 , the USSR had collapsed , Iran was increasingly ostracized , the Gulf Sheikhdoms kept giving India the short shrift favouring Paxtan over India especially over Kashmir in which the Mullahs too contributed to making our lives miserable.
Not many people know that there were local Shi'a terrorist groups operating in Kashmir funded & trained by Iran . It's one of our best kept secrets. That's another reason we were trying for a diplomatic break through with Iran which came about in 1990s.
Hence my earlier post our relationship with Iran is more or less the same as it was during the Shah's rule