The following is an overview and sketch of just how and where the US is collapsing. It's lightly sauced to be sure; but then again, Google is your friend.
Policy and process
Once-capable foreign policy agencies are being hollowed out from within. Experts are ignored or attacked while the US administration, in the person of whoever the President favors this week, pursues the monomaniacal interests of one man. The National Security Council, the State Department, the Pentagon's analysts, the intelligence community no longer guide the policy process. They have been replaced by the six fireflies bleeping in a jar that pass for the President's mental processes and that determine today's policy. Tomorrow's can, and probably will, be something entirely unrelated.
Western hemisphere
Other than returning US-Cuban relations to their previous, unproductive and unhelpful, state, events in the hemisphere unfold with little US involvement. If the US administration ever had a plan or policy toward Venezuela it is by now moribund. Bolivia's recent crisis caught the US on the back foot, as did Chile's. Threatening noises from the US over Nicaragua's simmering unrest are not nearly enough to change the Ortega regime's bad behavior. And in the face of continuing migration mostly from Central America, fueled by intolerable living conditions, the US has responded with little more than xenophobic fear and stillborn plans for a wall that wouldn't work even if a foot of it had been built.
Europe and Russia
Where the US is not marginalized in what is arguably the most important region of the world in which it formerly acted, it is uninvolved. Moscow has a free hand in its "near abroad," with the US administration reluctant to even condemn its excesses, much less actively oppose them. On important transregional issues such as climate change and human rights, the US no longer leads. Since power abhors a vacuum, other nations will take its place, sooner rather than later. Its most steadfast, reliable and trustworthy allies are not waiting for the US to recover its influence; they are rapidly making and implementing plans for living in a world in which the US no longer counts.
East Asia and the Pacific
Having blown up the multilateral trade agreement designed to counter Chinese influence and replaced it with precisely nothing, the US is seeing more and more nations in this region cozying up to its most dangerous rival, including most recently South Korea. Other than playing Chicken of the Sea it is doing nothing to counter China's island-building scheme, and nations such as the Philippines, Vietnam and Indonesia are taking notice. Japan and the ROK are at loggerheads; the US does nothing, proposes nothing. North Korea policy is nonexistant. There are no working-level contacts as Kim can always cajole Trump into giving him exactly what he wants while he keeps his nukes and missiles.
South Asia
Leaving the quagmire in Afghanistan may well prove more damaging than staying in. Having been caught in a lie over Kashmir, neither the President nor any other US official has any credibility vis-a-vis India or Pakistan.
Middle East
The Turk bent the US administration over to clear the way for its punitive expedition in Syria, neutralizing the US's best ally in the area and threatening to revive ISIS. He is also cozying up to Russia despite NATO. Iran, free of any constraints the discarded nuclear agreement might have carried, pursues its interests with a free hand; another consequence of turning Iraq from its rival in the region to a hot mess at considerable cost in lives, treasure and sacred honor. The abortive "peace process" zeroed out US credibility with the supporters of Palestine and now its main beneficiary has been indicted for corruption so rank it only pales in comparison with that of the White House. Trump and his son-in-law have thrown in their lot with Mister Bone Saw, spreading blood, devastation, death, war and horror across the region and winning exactly no friends for the US.
Africa
If the US administration has any attitude toward Africa other than calling it a collection of "shithole countries" it has yet to be detected or described.