Considering the fact that the financial system is pretty much unified already (in terms of influence, not direct value), politics should change according to it.
But there is a big problem.

in order this to function, all the people, whatever their nationality, must have equal constitutional rights, so that if I am an American soldier and I go on rampage, killing civilians, then the punishment be not depending on the nationality of the civilians I killed, and this do not work, simply because every country has its own laws, which if you bypass them to formulate the new law, then the judiciary system of every country would be hurt, suffering from lack of credibility and could finally be erased, mostly by force (civilian wars), by people who will consider that their national identity is in danger.

Extending the federal law in the US to global scale is theoretically good, but the implementing of it is extremely hard, especially with the resistance of Russia, China, North Korea, Iran, and all those who expect from their superior geopolitical position give them the advantage.

haha yeah right. because the U.S has been so successful implementing :democracy" in all the countries it invades. Yet the awesome U.N will be able to do it. LOL. You guys are delusional.

These are the issues I was already addressing .

"Considering the fact that the financial system is pretty much unified already (in terms of influence, not direct value), politics should change according to it."
"But there is a big problem": you

"Extending the federal law in the US on a global scale" should be a decent example, nothing more. I don't imply that the UN should be under US command.