The real question is how would they govern?

Superman would start a war with Iran because it's the American way. Goku would start a war with Iran because he hears they are really strong. Goku would probably reform the education system to focus on PE and combat sports, Superman's anti-billionaire bona fides are relatively strong but he is a capitalist dog at his core.

I would choose Goku as the lesser evil. Yes he'll start wars with a bunch of different countries, but he'll insist on going and fighting them himself as opposed to sending in the Marines or conducting airstrikes.

I feel like of the two Goku would be a much better candidate on the Palestine issue. Superman would team up with his Israeli colleague Sabra, Goku would look at Hamas resistance fighter strapping bombs onto tanks, remember his own battle with the red ribbon army, and go to town on the IDF.