Diplomats and politicians voice concern over Vance's repeated criticism of US aid to Ukraine.
European politicians and diplomats had already prepared for changes to their relationship with the US in the event of a second Donald Trump presidency.
Now that the Republican candidate has chosen Ohio Senator JD Vance as his running mate, those differences appear even more stark on prospects for the war in Ukraine, security and trade.
A vocal critic of US aid to Ukraine, Mr Vance told this year’s Munich Security Conference that Europe should wake up to the US having to “pivot” its focus to East Asia.
"The American security blanket has allowed European security to atrophy," he said.
He might be my worst nightmare: an intelligent, opportunistic, disingenuous, duplicitous, hateful, proudly misogynistic, election-denying, authoritarian-curious chaos agent, wrapped in a young relatively attractive white man’s body. He will do a far better job than Trump ever could at making their sick regressive and paternalistic fantasies come true for all of us.
Don't think for a minute that Vance won't throw the orange clown under a moving train once he positions himself in power. The orange felon's days are numbered.
He might be that now, but Trump is gonna make sure to break him of that competence and any accompanying confidence.
The man cannot handle the idea of someone being in a position to replace him even if he dies, because to him that means they can replace him in a plot to kick him out.
I could certainly imagine him holding the Mearsheimer position of "Russia is America's natural ally against China", though to be clear this is me speculating