Heads of state visits
In the reality-based universe, which we have not been living in for some time now, heads of state and heads of government exchanged visits for any number of reasons. Goodwill. Show of solidarity among allies. To sign agreements that diplomats had negotiated prior to these visits. To discuss/solicit financial aid (again, after discussions & negotiations, etc.). You get the idea. This was all sort of routine, and really intelligent government officials coordinated among themselves to make sure everything came off smoothly. Speech writers were given directives, note takers took notes, counterpart met counterpart.
We no longer live in this reality-based universe. A buffoon is in the White House. His word isn't worth the pixels used to express them, and there are no longer any professionals in place to do the groundwork, etc., etc.
Given all of this, why would any head of state visit the US to meet with this international embarrassment. They have little or nothing to gain. And why would any rational, intelligent, democratically elected leader extend an invitation to this utter moron? Again, what do they possibly have to gain?
Let this carbuncle meet with all the dictators he likes. Let him invite the dictators to the White House - or whatever it is you call that big white building on Pennsylvania Avenue - but leave the rational world leaders out of it. Let them do their thing and cut us out. When a rational human is elected in 2020, we can begin the long, hard slog to becoming a world citizen again. Until then, skip the invites.