It's pretty interesting. The only people Trump respects are kings and dictators. You'd think that he wouldn't respect Chuck, who has almost no real power, only soft power. But, then you look at how he loves gilded things, and you can see that what he's aiming for is the jewels and gold of the monarchy. So, he looks up to Charlie. And, it's going to be really awkward when HRH reminds him that he's also the king of Canada.

For Chaz, this is an existential thing. Since WWII the crown has been progressively losing territories. Many former realms have become republics. But, Liz and then Chucky have managed to keep them in the commonwealth. Losing a territory over which he's still the actual king would be proof that he's really just a figurehead and the monarchy is obsolete. OTOH, if he could use his soft power to protect Canada, he could show some people that the monarchy is still relevant, and maybe keep some countries like Australia from swapping their monarchy for a republic.

Remember when Trump behaved like a dick to his mother? I bet he remembers.