He is unique in that he seems to have absolute control over the Republican base which makes all internal party checks fail. The rest is provided by a hyper polarized media landscape and a conservative supreme court majority that seems to be open to radical upheavals. The combination of all three has rendered the constitutional safe guards ineffective. In other words, we seem to have run into an edge case in the US constitution.
The supreme court won't change materially in the near future and likely the polarization will continue, but it's hard to image someone in the future with such an absolute grip on either party. So, hopefully a soft restart of the system in 2028 will be the last of this edge case for a while. That's the hope, anyway!
The two countries have far more in common shared interests than differences, so odds are things will drift back to normal in the future.