Donald Trump was having a horrible month. Then Howard Schultz gave him a chance to flex his inner Biff.

Trump hopes, hopes, hopes Schultz runs for president.

And so President Biff did what his role model, the ruling oaf in “Back to the Future,” did to Marty McFly: called him chicken.

Schultz, the former CEO of Starbucks, “doesn’t have the guts to run for president,” he tweeted.

That should do it, Biff.

Judging by Trump’s horrible approval ratings – cumulative...