John Kasich has emerged as one of the “top second-tier” candidates in New Hampshire, running third in the RealClearPolitics average — a little behind Ted Cruz and a little ahead of Marco Rubio.

But The Huffington Post reports some mystery dark money against Kasich is about to run a 30-second spot attacking the Ohio governor on “Common Core, Obamacare, Medicaid expansion, and raising taxes.” A Democrat dirty trick? Possibly, but the ad is factual.

Kasich’s firm support for Common Core is his Achilles’ heel in New Hampshire, and I am guessing he is about to find that out as New Hampshire voters find it out.

Maggie Gallagher is a senior fellow at the American Principles Project.