There are completely new things that are not all feasible and what is feasible is not easily feasible.
For example, Donald Trump confidently declared that he could end the Russia-Ukraine conflict in just one day. Everyone knows that Donald Trump intentionally exaggerated his "problem-solving ability". Therefore, before he could meet Russian President Vladimir Putin and even talk directly to him on the phone since he was elected President of the United States, Trump had to increase the time frame from one day to six months.
Or Donald Trump has left open the possibility of using military means to control the Panama Canal and Greenland. The US returned the canal to Panama in 1999. Greenland is autonomous under Danish sovereignty. The governments of Panama and Denmark have both flatly rejected Trump’s intentions and threats. The people of both places have also strongly opposed it. International law does not allow anyone to do what Trump intends to do. Denmark and the US are both members of NATO and the US is committed to ensuring the security of NATO members when attacked.
Mr. Trump is still vague, just vague but not yet a clear intention to rule, intending to change the name of the Gulf of Mexico, which has been used for more than 400 years, to the Gulf of America. Mr. Trump can do this for the United States, but whether the outside world will use the new name or not is another matter. The only thing among the strange decisions that Mr. Trump has promoted in the media so far is to impose trade protection tariffs on goods of some export partners to the US market, but the price that the US has to pay here is retaliation and it may be more harmful than beneficial in the long run and in certain cases.
It is said in advance but it is not easy for Mr. Trump to overcome this, simply because although the United States is still very powerful in terms of military and economy, science and technology, and influence in international relations and world politics, it is not to the extent and sufficient to be able to do whatever it wants with the world outside the United States. Mr. Trump and his team of associates are certainly very clearly and fully aware of this.
The explanation is that Mr. Trump can only hold power for one term, which means only 4 years. For at least the next 2 years, the Republican Party controls both houses of the legislature. Mr. Trump currently controls this party. It can be said that Mr. Trump is at the peak of his power, so it is understandable that he is confident.