I doubt rhe repulsive Trump regime actually bring us any closer to World War Iii but they signal a green light to Russia and China to also act as unlawfully as they see fit in with such as elements of the former Soviet Union and Chinese Taipei.
Suits them all and not a lot anyone else can do about if. Or that each of the horrible 3 will do about each other.
FWIW ( very little really in the grand scheme of the awful effect on so many people's lives ), if Trump was to follow through by force on Greenland in the next 4 months or so, I would expect Denmark ( which aleady has separate issues with FIFA ) to boycott the FIFA World Cup and I would hope that all the other UEFA countries at least would follow suit. But ultimately he would no doubt get away with it politically and militarily.
I think invading Greenland would tear NATO and Europe apart, which ultimately seems to be his aim. US of A is returning to the Wild West culture. Hopeful it wont bring on WW3, only because there is too much money at stake. With Trump a that is all that matters. Not environmental impact, morals and values just dirty dollars. Rant over!
there are signs though that his own electorate are no longer as supportive as they were (as in MAGA supporting folks) and some of his own former accolytes are turning. With luck, it will be about riding out this next couple of years, ensuring he finds no way to get another term (and he is going to be an older man when that comes about anyway) and hoping the next person in is more moderate and more diplomatic, whichever ever party they come from.
He wont take Greenland by force - this is bullying, makes lots of big noise and threats and then use it to leverage something acceptable. He will either buy it or get full military access rights and some sort of mineral rights deal and that will see him off in due course. It is all about the money.