They have to look out for their countries and therefore meet with Trump to extract concessions or "deals" from him. They know that all they have to do is act as if they take him seriously, praise him and manipulate him to give them what they need.

The 30% tariff is now 15 %. Mission accomplished.

Tomorrow, he may wake up and decide that it's now contingent on blowing up all the windmills. Or that it's an unfair deal made by Obama and now it's going to be 45%. Or he needs a brand-new chrome-plated gold washed tank to drive on the golf course. Not a bribe, of course - it'll go to his library as soon as he's out of office. Or...whatever rabid raccoon virus plops into that rancid skull of his.

It's not a deal. You can count on a deal.

They have seen wannabe emperors come and go, and royalty go insane. They are playing the long game. Trump is toast, it seems, but dangerous in the short term.