Jonny Weeks/Pool via GettyLONDON—The main aim of President Biden’s European tour this week has simply been to show that the United States “is back!” at the heart of the Western diplomatic consensus.Unfortunately, the world is a little more complicated than that. By Saturday night in England, it was beginning to look like the White House had been a touch over-confident in just how far the charms of Biden would take him in persuading other G7 leaders to swallow all of his policy positions. Even th