Right up to November 3, Barack Obama absolutely must stay on the campaign trail for Joe Biden, for two fundamental reasons. One, Joe Biden is incapable of campaigning for anything other than ultra-limited appearances of short duration. Biden’s handlers know that every time he speaks for more than a few minutes, even a few miles away from home, he loses thousands of voters. Two, more compelling for Obama, he must cover his own tracks. Helping Biden get elected is the only possible way, however far-fetched that notion. Last August, it was revealed that Obama spied on the Trump campaign and knew...