Answer
The world is very old and has survived quite a few disasters. When a jesting figure like Donald Trump may find himself in a position of power for a while, she will also get over this. Perhaps the question posed would be better reformulated as “How much damage can an inept President of the United States do?”
The US is still undeniably the most powerful country in the world and the president is the most powerful man in that country, but that doesn’t make him supreme. After all, the US is not an absolute monarchy or a totalitarian dictatorship, but as far as possible a mature democratic society. Fundamental in such a society is the separation of powers. This is the division between executive, legislative and judiciary.
Specifically in the case of the US, this means that a president and his government can and must run the country, but that they must comply with the laws made in parliament (this is called “congress” in the US). and that those who are disadvantaged if they do not do this can challenge this in court. So a radical president can try to abolish all kinds of government agencies and legislation that exist to protect worthy interests – such as those of workers or the environment – but he will have to justify this in court again and again. The final word on this matter then ultimately rests with the Supreme Court, where nine highly skilled judges watch over the law and the constitution. They are indeed appointed by the president, subject to the approval of parliament, but once they are appointed they cannot be removed or replaced. The president has no power over them.
However, your concern may be more in the area of ​​international relations. It is certain that a stupid and foul-mouthed figure in the president’s chair can make a lot of enemies even more hostile, undo newly found detentions (Cuba, Iran,…), alienate old allies and offend third powers. So it really wouldn’t be good for international relations if someone like Trump became president. Not for the US, not for its allies (that’s us), not for the rest of the world, and certainly not for the populations of all sorts of roaring or potential hotbeds of conflict.
Foreign policy, however, is not conducted by the president alone. The US has very extensive and professional diplomatic services that can smooth out at least some of the folds in all kinds of incidents. In addition, serious diplomatic riots can quickly arise, but most stable states have a great aversion to real wars. This also applies to countries like China, Iran or Russia (a real war is different from some skirmishes in Georgia or Ukraine). After all, their interests also benefit best from a certain stability.
This is not only to say that they themselves will not soon plunge into a world war. It also means that they will make certain efforts to control all kinds of less predictable regimes in their own sphere of influence (think of North Korea, for example).
Furthermore, the democratic nature of American society again offers a safety valve here. After all, the US has an impeachment procedure, the so-called “impeachment procedure”. This means that, if a president does his job so badly that it is not justified to leave him in power, parliament can remove him from office. This procedure is difficult and involves many steps, but it is not entirely unthinkable that it would be applied to a president whose policies are causing undeniable serious damage to the economy, peace and security.

Answered by
Olivier Eloot
http://www.ugent.be
.