Donald Trump may be behind in most polls but one veteran New York prognosticator still predicts he will win come Election Day. I think he was the strongest candidate in the primaries and that he will prevail, Helmut Norpoth, a political-science professor at SUNY Stony Brook, told The Post on Monday, even as the RealClearPolitics average shows the Republican candidate trailing Democrat Hillary Clinton by 6.1 percentage points.