When I was going through Quantico in 1968, there were several senior NCOs..lifers..on their last duty station before retiring, who had fought at Iwo. Veterans of other island campaigns, the consensus was that Iwo was by far the worst, in terms of the intensity of the fight.. The "misery factor" was much greater on Guadalcanal, because that lasted for 7 months, compared to 7 weeks on Iwo, and for much of the battle for the Canal, the Marines suffered from a severe lack of supplies, as well as intermittent naval gunnery and air support.
The cost, more than 6,800 KIA in that short time, was horrendous. I used to take some comfort, and pride, from the fact that over 2,500 emergency landings took place on Iwo (the vast majority by B-29s bombing Japan) and thus one could assume that over 20,000 lives were saved by capturing Iwo. Also, at the time, very few commanders knew that the island was needed as an emergency field for the bombers that would be carrying the atomic bombs. The ides of the "Enola Gay" having to ditch in the Pacific en route to Japan gave everyone involved in the mission nightmares. At that time, we lacked enough fissionable material to make another bomb.
Iwo Jima pretty much defines the Marine Corps..It is a central part of our ethos, our DNA..the bravery, courage, sacrifice..raising the flag, the iconic picture, the Marine Corps Memorial in DC depicting that act, "uncommon valor was a common virtue," the Medals of Honor ( 22 to Marines, 5 to Navy corpsmen; 14 posthumusly) representing almost 30% of ALL MoH's awarded to Marines during the ENTIRE Pacific campaign. IOW, that sacrifice is sacrosanct.
As a rule, I don't like revisionist history. At its worst, it's Monday morning quarterbacking, where hindsight is always a perfect 20/20. However, recently, military historians have begun to honestly question and explore whether the campaign for Iwo was necessary. A few points are being raised:
1. Iwo wasn't needed for the emergency base for the atomic missions. We'd already taken Okinawa, which could have worked.
2. Careful examination of flight logs shows that as much as 90% of the "emergency" landings on Iwo weren't true emergencies. The bombers might have made it back to Tinian, or there were other captured airstrips that could have been used. No one faults an aircrew, heading for Toyko ( or returning) if an engine is running hot, for landing at Iwo for repairs..they'd be crazy NOT to do so...but that doesn't then mean that all 2,000+ B-29s would have had to ditch in the Pacific if he hadn't taken Iwo.
3. There were no Jap fighters on Iwo that could have posed a threat to our bombers, and any attempt to send more to the island could have been stopped by stationing a carrier group in the area to intercept them. The Japanese on Iwo could have been starved out, they'd have run out of supplies in a few months..
I think we'll start to see some serious study and discussion about Iwo Jima in the next few years. The import ant thing is that doing so in no way detracts from the courage, and sacrifice, of those who fought, and died there.
The landings on Okinawa started on April 1, 1945, after the Iwo Jima campaign.