Five months after the hostage taking, Carter ordered military action to rescue them. The mission failed.
Say what you will about that mission. Feel free to criticize. But I don't see how that demonstrated a "lack of spine".
If the mission had succeeded, Carter probably would have been reelected and declared the new Eisenhower.
Yeah, it takes "spine" to send other people out on a poorly planned mission. Some of them died for nothing as there was no chance of success.
Why are you defending Carter?
His Rules of Engagement for the mission were very restrictive. He insisted on lots of practice for the mission. He insisted on such a low risk approach, that they would not allow the best forces for the mission to be used, nor would they allocate sufficient forces. There were not enough helicopters, and the "low risk" ROEs dictated that Marine or Navy helicopters be used, rather than the Air Force ones designed for just such a mission, for fear that someone might notice the Air Force birds on the Navy carriers. He didn't allow any prepping of the battlefield, and really treated the whole thing like a stateside SWAT affair. There was no air cover provided, which all by itself is close to a criminal act.
I remember during the hostage crises discussing how we would set up a rescue mission with a guy who worked for the same company, and who I'd known when we were both Air Force officers on active duty.
Our sketchy solution. Send in the B-52s, many cells of them, bomb all the approaches to the location where the hostages were being held, plus radar sites, naval bases and air fields. The last cell, or two or three, would actually be C-141s or C-5s, with a whole bunch of airborne troops, who would drop in, rescue the hostages, and then wait for the helicopters to come get them all. It would have been a much larger mission, and it would have broken a lot more stuff and killed a lot of Iranians.
We knew that it was probably a bit too ambitious, but would never have guessed at such a mission as was actually laid on.
But even given that the mission that was laid on failed, there were no further missions, no retaliatory bombings, not even any threats to do so. No "Release them, or else".
With Ronald Reagan they knew there would be an "or else", so they released the hostages on his inauguration day. With JC, they didn't believe in "or else", rightly as it seems.