Donald Trump’s strategy in this campaign has been fairly clear from the beginning: Drive up Republican support among white voters in order to compensate for the GOP’s shrinking share among the growing nonwhite portion of the electorate. And Trump has succeeded in overperforming among a certain slice of white voters, those without a college degree. But overall, the strategy isn’t working. Trump has a smaller lead among white voters than Mitt Romney did in 2012, and Trump’s margin seems to be falling from where it was when the general election began.

Four years ago, Romney beat President Obama among white voters by 17 percentage points, according to pre-election polls. That was the largest winning margin among white voters for any losing presidential candidate since at least 1948. Of course, even if Trump did just as well as Romney did, it would help him less, given that the 2016 electorate will probably be more diverse that 2012’s. And to win — even if the electorate remained as white as it was four years ago — Trump would need a margin of 22 percentage points or more among white voters.

But Trump isn’t even doing as well as Romney. Trump is winning white voters by just 13 percentage points, according to an average of the last five live-interviewer national surveys.1 He doesn’t reach the magic 22 percentage point margin in a single one of these polls.