The farther we get from the Democratic convention, the worse the polls get for Trump, it seems. A new McClatchy/Marist National Poll shows Hillary Clinton with a commanding 15 point lead over Trump, leading him 48-33.

This poll is significant for a number of reasons. First, most of the polls released earlier this week were from over the weekend after the DNC, directly in the afterglow of the convention, and subject to the vagaries of weekend polling. This is a weekday sample, which also means that it is the first sample that has pulled significantly from voters who were exposed to Trump’s disastrous news week and the Khan controversy in particular.

How bad is this poll? Well, if it’s true, it would portend the second-worst landslide of the last 50 years. Only Walter Mondale has lost by as many as 15 points in the modern political era. The other relatively easy wins over the last several elections have not been close. Obama beat McCain by a mere 7 in 2008. Bill Clinton’s alleged whitewashing of Bob Dole in 1996 was a 9 point win; ditto George H. W. Bush’s shellacking of Dukakis in 1988.

But even the really bad historical drubbings that were worse than 15 – points – Mondale in ’84, McGovern in ’72 and Goldwater in ’64 – pitted challengers against incumbents. The last time any major party candidate lost to a non-incumbent by as many as 15 points was probably 1932, when the incumbent Herbert Hoover lost to FDR.

This election really could be historic after all.