Donald Trump looks increasingly likely to be the Republican nominee. Hillary Clinton looks increasingly likely to be the Democratic nominee. And Clinton looks increasingly likely to stomp Trump in a general election:
As you can see on the chart, Clinton and Trump were about tied back in February. But the more the American people have seen of Trump's campaign, the less they've liked him. Both Clinton and Sanders have pulled far, far ahead of Trump in general election matchups.
This is, according to political scientists, around the time when general election polling becomes predictive of the actual vote. "Were this a few months ago, I'd say, 'What's the big deal?'" Christopher Wlezien, a political science professor who's done a lot of work on election polling, told Vox back in March. "But polls today are much more meaningful than they were 90 days ago. And the polls today are much less favorable for Trump."
To put Trump's deficit in perspective, at this point in the 2012 campaign, Barack Obama led Mitt Romney by 2.7 percentage points — pretty close to Obama's eventual 3.9 percentage point margin of victory. And Romney wasn't as well-known or as polarizing as Trump is, so he probably had more room to change minds than Trump does at this point.
This isn't, by the way, a simple function of the Democratic Party having an advantage over the Republican Party. John Kasich, for instance, leads in polls against Hillary Clinton, and so did Marco Rubio before he dropped out of the race. These polls, rather, are a function of Republican voters choosing their least electable candidate to face the Democrat.
For Trump to trail Clinton by almost 10 points is a disaster for the Republican Party. These are the sorts of numbers that could lead to Democrats taking back the Senate. They're the kinds of numbers that give Democrats an outside shot at taking back the House. They're the kinds of numbers that give Clinton — a polarizing candidate in her own right — the possibility of a landslide victory.
It's early yet, of course. And plenty can and will happen between now and November. But these are terrifying numbers for Republicans. These are not the numbers you want to see when you're nominating one of the best-known celebrities in America, and when your own party isn't even united behind him.