The first American tourists began appearing on the Champs-Elysées in Paris on Wednesday, just as Joe Biden was touching down in Britain for his presidential debut on the world stage. The message that he’s brought with him is a single, unified theme — one he’s enunciated at virtually every opportunity since his arrival and that he clearly intends to repeat at the G-7 summit this weekend and that NATO summit that will follow. That message? America’s back. And you can count on us.