Few things are more certain in politics than Donald Trump attempting to deflect from a negative news story by creating a fuss over another. That’s the best way to read the President’s taunt Friday that Russia should be readmitted to the G-7 democracies whose leaders are gathered for their annual summit this weekend. But this latest smoke bomb of distraction could still do needless harm to Western unity on Russia.
“I have been Russia’s worst nightmare,” Mr. Trump said before departing for the G-7 in Canada, comparing himself,...