Democratic presidential candidate Hillary Clinton emphasizes human rights as she spoke to supporters after conceding to Bernie Sanders in the New Hampshire primary. (Reuters)

Update: The Clinton campaign conceded at 8 p.m. Eastern time, as the last polls in New Hampshire were closing. The below post had been updated.

There is a quirk in the Democratic presidential nominating calendar.

Nevada, which is generally thought to be the fourth of the four early states, will actually be the third to vote. Its caucuses are next on the nominating calendar and will take place Feb. 20 -- the same day Republicans hold a primary in South Carolina. South Carolina Democrats go to the polls a week later, on Feb. 27.

And if you're Hillary Clinton, that's not ideal.

There is this perception that New Hampshire, which Bernie Sanders won Tuesday, is too white and too close to Sanders's home state of Vermont for Clinton to win. After New Hampshire, though, the states get significantly more diverse; basically every one of the next couple dozen states to vote is less white than Iowa and New Hampshire.

We've called this Clinton's "nonwhite firewall." Basically: More-diverse electorates start voting, and Clinton has a better chance of putting together a series of wins and ending Bernie Sanders once and for all.

But while Clinton might indeed be a shoo-in in South Carolina, that isn't so clearly the case in Nevada. Witness this tweet Monday from chief Nevada political analyst Jon Ralston:

Technically, Nevada is actually the more-diverse state of the two. Non-Hispanic whites comprise just 51.5 percent of the population in Nevada, compared to 64 percent in South Carolina. Nevada has many Hispanics, while South Carolina has a large black population.

But to assume that both play to Clinton's strengths in similar ways is to miss the point. For a few reasons:

1. While Nevada is even more diverse than South Carolina, its caucuses have been much whiter.

According to 2008 entrance polls, just 15 percent of Democratic caucus-goers were Latinos, even as they were 24 percent of the population of the state.

This has plenty to do with the fact that, while about a quarter of the state was Hispanic, just 12 percent of eligible voters in Nevada were Hispanic, thanks to huge populations of young and undocumented Latinos. In fact, in 2008, black voters actually comprised the same portion of the caucus electorate as Hispanics -- 15 percent -- despite being less than 10 percent of the state's population.

That black turnout likely had at least something to do with the potential first black president being on the ballot -- something that will not be true in this year's caucuses. Thus, even as the state's Hispanic population has climbed from 24 percent to 28 percent over the last eight years, we could very well see an electorate that is no more diverse than it was in 2008.

And it wasn't a very diverse electorate. In fact, it was nearly two-thirds white -- compared to 43 percent in South Carolina that year.

2. Latinos are less overwhelmingly for Clinton

An automated Public Policy Polling national survey last week showed Clinton leading Sanders by 74 points among black voters, but by just 12 points among Hispanics.

That's one survey, but it's clear that Sanders's problem is much more acute among black voters, who are a much bigger presence in South Carolina than in Nevada.

3. Nevada is a caucus state

This is a format that requires a time investment and rewards impassioned supporters, who are more numerous on the Sanders side of the 2016 primary, all signs indicate. Clinton will certainly have a formidable operation on the ground in Nevada, but as we saw in Iowa, intensity can make up for a lot.

So could Sanders actually win Nevada? It's very difficult to say with any certainty, given the dearth of quality public polling. The last high-quality survey from CNN-ORC in October showed Clinton leading Sanders by 22 points (58-36) in a race without Joe Biden and with Martin O'Malley. Of course, back then, CNN's polling showed Clinton ahead in Iowa by 18 points. A lot could have changed in Nevada, too.

But the atmospherics are there for a competitive state -- one that could extend Clinton's misery for just a little while longer or at least be a headache, before her campaign can fall back on the much more solid portions of her firewall.

Democratic presidential candidate Hillary Clinton emphasizes campaign finance reform and economic policy as she spoke to supporters after conceding to Bernie Sanders in the New Hampshire primary. (Reuters)