I don't know enough to provide you with a good answer, but we know that Oshii believes that Japan was used as a "shield" to America's "sword" in the Cold War. I think this was mentioned in 2nd GIG by the Tachikomas. I also think one of the Patlabor movies mentioned something about Japan helping to manufacture weapons for America or something.
The US has military bases setup in Japan, and the US used these bases during the Korean and Vietnam wars, I think. As such, I'm sure the Soviet Union had nuclear weapons trained towards Japan. This probably made many Japanese, especially those of Leftwing politics, frustrated, as they could potentially be pulled into a conflict they wanted no part of. This is the "shield" part that the Tachikomas are probably referring to. Other leftists may have felt that Japan was being forced to help kill their own political brothers (the communists in North Vietnam for example), or to prepare for an invasion of China.
Meanwhile, some Right wing Japanese probably felt that the US was helping to defend them from the so-called "Communist domino effect" that was supposedly rolling over all of the world, and that if America was not there, Japan would be ultimately taken over by the Reds. This was, after all, a strong reason Hitler and his Nazis launched a war on the Soviets. They felt that the communists were trying to take over Germany, especially after the failed communist uprising took place in Berlin with the Spartacists League. So these right-wing Japanese, who I think are represented by Gouda and the right-wing Cabinet guy with the white hair and glasses, feel that the US is ultimately a great ally, one that is bringing Japan wealth and security.
There are even some theories out there that the Japanese mafia, the Yakuza, have ties to the American military/intelligence communities. Supposedly the American mafia played a supportive role in the anti-communist conflicts of the Cold War, too. So I guess it's possible the Yakuza did the same. Organised crime is usually friendly towards fascist and far-right movements, as their philosophies are not very Marxist to say the least.
But, all this is just guessing on my part.
