One world government would be so ineffective, totalitarian and corrupt that it would be in a state of either constant uprising or permanent heavy handed suppression. It would definitely not be "peaceful" except in the sense that an effective police state is "peaceful" because anyone who suffers from it is crushed, before they even get to the point of being able to disrupt the peace.

How would an ineffective, totalitarian and corrupt goverment manage to supplant all the existing ones? I think that if a world government manages to form, it cannot be any of those things. To unite all the peoples of Earth it has to be efficient, democratic, and just.

By exploiting people with views like yours, and by hiding the truth about it's own nature? Look at the EU for an example of how to do this. The hard core remainers are all convinced anyone who doesn't like the EU is brainwashed, racist, stupid or all three but they struggle to keep up in a debate involving the details of what the EU really is and how it works. That's what converted (deconverted?) me: realising at the start that my pro-EU position was based on the sort of wishful thinking your comment implies. It's all about cooperation and world peace, right? Then I listened to the Brexit campaigners and discovered that I had no idea what was really going on in Brussels. It was very far from the friendly face.

One planet means world peace? Wasn’t clear from the context.