What if...Pearl Harbor had been averted?

I read a book not too long ago about a scenario where, instead of the Japanese airplanes being mistaken for inbound B-25s (B-17s?), they were properly identified as not being friendy. All the military bases on Hawai'i were put on alert and the Army Air Force put their planes in the sky and thwarted the Japanese bombing of Pearl Harbor. My question is: how would the U.S. have been viewed had we attacked the Japanese fleet before they could attack us? Would we have been viewed as the aggressors? Would the people of the U.S. have been as supportive of a war where we basically struck the first blow?

 

The planes are correctly identified and just like that at 7am on a Sunday morning enough fighter planes are put into the air to completely thwart the attack? really now...

 

What would happen largely depends on where and when the Japanese fleet was detected and possibly attacked. Six Japanese carriers have no business suddenly appearing unannounced 200 miles off Oahu; if they are attacked there, it would make no difference whether they had launched their planes or not, people would realize their intent and the feelings would be the same as historically.

If the Japanese fleet were intercepted earlier, somewhere in the North Pacific, it likely wouldn't be attacked. It would simply be watched as it turned around and slunk ignominiously back to Japan. But the war would still occur, since the Japanese plans were to launch simultaneous surprise attacks on the Philippines, and Malaya. And the American public would still be outraged at Japanese duplicity since the intent of the Japanese carriers would be clearly recognized. Understand that a lot of the outrage against the Japanese was because these surprise attacks were launched while Japan was supposedly negotiating in good faith with Washington to lessen the tensions between the two countries.

BTW, it was B-17's that the Japanese planes were mistaken for on the morning of December 7, 1941. And even if they had been correctly identified it's doubtful that many interceptors could have taken off in the hour or so that remained for the defenders of Pearl Harbor. There was no command and communication structure in place to disseminate the warning, and no stand-by interceptor units on call for instant response. Those American lanes that did manage to take off historically were mostly at the initiative of individual pilots.

 

According to SCR-270 radar - Wikipedia, the free encyclopedia the raid was detected 55 minutes out. If it was correctly identified I don't see the info getting to the fighter fields for at least 15 minutes or so. Very few pilots were available at that time so planes probably wouldn't be getting into the air until the raid was less than half an hour out. On the other hand the Army AA guns might actually be manned and have some ammo available at least for the second wave. The Japanese torpedo bombers would likely be shot up pretty bad as they would be an obvious target both for fighters just taking off and for AA. If the navy is given half an hour some of the ships may make it to sea in the time before the first wave attacks and by the time the second wave gets there most will unless someone has blocked the entrance. The ships should all be water tight and the AA guns manned by the time the first wave gets there as well. The Japanese will loose considerably more planes but probably not any CVs. The US will likely sustain a lot less damage.

 

Hmmm, here's a thread that I think would be useful to review for this what if.
http://www.ww2f.com/what-if/22652-what-if-fighters-pearl-were-scrambled-time.html