This is the Ted Cruz moment. There was nothing inevitable about it, nor is there anything conventional about him. Born in Canada, elected to the Senate from Alberta's muscular cousin, Texas, Mr. Cruz has until this month been overshadowed by his slightly younger fellow Cuban-American, Sen. Marco Rubio of Florida. No more. Cruz has soared to the lead in almost every poll in Iowa, eclipsing even Donald Trump, and ranks second to the billionaire businessman in almost every national poll. If there is an alternative to Trump right now -- and remember, as a cautionary note, how Republican polls and...