Donald Trump is the most unpopular nominee in modern history, and he could still be elected president on Tuesday.

How could this happen? Part of it is that Hillary Clinton is also unpopular. But most of it is partisanship, pure and simple.

It's actually pretty astounding if you look at all the numbers just how many areas Clinton leads in.

A CNN/ORC poll released last week showed Clinton led by large margins on the following issues and characteristics:

  • Foreign policy (58-38)
  • Temperament (59-32)
  • Can handle the responsibilities of commander in chief (53-40)
  • Is a person you admire (40-29)

She also led by smaller margins on:

  • Nominating Supreme Court justices (51-45)
  • Having a clear vision (48-41)
  • Will stand up for people like you (47-43)

She and Trump were basically tied on:

  • Terrorism (49-47 Trump)
  • Immigration (49-48 Clinton)
  • Being a strong and decisive leader (47-45 Trump)
  • Who is more honest and trustworthy (43-40 Trump)

Trump, meanwhile, led by a significant margin on just 1 of 13 issues and characteristics tested: the economy, where he beat Clinton 52-44. That is a big issue, yes — just ask Clinton's husband — but given all of his other deficits?

If you look across other polling, this isn't unusual. About the only other issue/characteristic on which Trump consistently leads is on bringing change to Washington. A Bloomberg News poll two weeks ago showed him ahead of Clinton on that measure, 63-24. Apart from the economy/jobs and change, though, Trump usually doesn't lead, and people see Clinton as being far more ready for the job.

And it's not just Democrats and independents who have real reservations about Trump in many of these areas. It has become clear late in this race that many, many Republicans will be holding their nose while voting for Trump.

A New York Times/CBS News poll this week showed a plurality of Republicans, 41 percent, said Trump has been bad for the GOP, while 39 percent said he has been good. (This is their nominee — a week before they're set to vote for the guy!)

In addition, about 4 in 10 Trump supporters have said:

And as the Pew Research Center showed this week, of Republican-leaning voters who didn't vote for Trump in the GOP primary, 59 percent describe him as “reckless,” 53 percent say he has poor judgment, and just 40 percent say he's moral, while only 28 percent say he's a good role model.

Despite these clear reservations, the Post-ABC tracking poll shows three-quarters of those GOP-leaning voters who voted for other Republicans are now voting for Trump. The Republican base is coalescing around Trump — despite these clear reservations about him — and that's a big reason he's got a fighting chance.

These Republicans aren't as enthusiastic as Bernie Sanders's supporters are right now, but they are considered likely to vote.

This partisanship isn't sufficient to win, but it kept Trump in the game for much of this campaign. His share of the national polls in a two-way race never dropped below 41 or 42 percent once the general election got rolling. And even at his depths, his average deficit was around 7 points.

Clinton clearly has her vulnerabilities, and it took Bernie Sanders supporters a while to come around to her. But their reservations about her simply aren't on the same level as the reservations about Trump that still exist in the Republican Party.

The one big negative Clinton has consistently had with even members of her own party is on honesty and trustworthiness, and that's no small thing. But Trump's numbers there generally aren't much better. There isn't a big bloc of Democrats who say Clinton isn't presidential, or that she's reckless. They don't say that she's bad for the party or has bad judgment.

Many Republican voters believe all of these things about Trump, but it hasn't been enough to sway them against voting for him. That's given him a fighting chance in this race that simply wouldn't exist if the country weren't so starkly divided on partisan lines.