It's easy to underestimate Donald Trump. The other Republican candidates in the race continue to do so, writing him off as a clown, a charlatan, a fool. Today, David French of National Review writes him off as a conventional Democrat: Trump doesn't threaten the Republican establishment because he's too conservative or too populist. He threatens the Republican establishment because he belongs in the other party. There's truth to this - there's a reason that Code Pink essentially endorsed Trump over the weekend, after Trump veered into Iraq trutherism and blamed George W. Bush for 9/11. And Trump, as I've written...