Close Cooperation with eachother. The USA can no longer be seen as a reliable partner with its wild ideological swings and a lack of strong commitment to the cause.
Make or break for a strong European State.
From a UK perspective we're absolutely fucked due to Brexit. USA is unreliable, detached from the EU, what's left? BRICS? Lol.
Shit.
Whatever you want him to do, the next guy would reverse it in 2 months. Well done USA.