Boris Johnson has rare powers. He's gonna need them

)Boris Johnson, Britain's next prime minister, is a pragmatist, and having been born in the United States, understands America as well as perhaps no other politician since Winston Churchill. He recognizes the paramount importance of the post-Brexit relationship between the United States and the UK. He has worked hard to forge a positive relationship with President Donald Trump at a time when other world leaders have found that difficult or impossible to do.

Indeed, when people liken Boris Johnson to Trump, the comparisons are often either overblown or superficial (the...