Tonight the Republican hopefuls gather to debate in Las Vegas. The focus for the combatants will be on winning the nomination, but there may be no better city in the country for understanding the challenges the GOP will face next November.
The political and demographic shifts in Sin City over the last 15 years outline the growing problems the GOP has had in presidential elections over that time.
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Start in the 2000 presidential race and walk forward through the next three elections and the trend is pretty clear when you look at the state of Nevada and Clark County, the home of Las Vegas.
In 2000 and 2004, Republican George W. Bush carried Nevada very narrowly. The key to those Republican wins? Democrats Al Gore and John Kerry won Clark in both races (Democrats almost always win big city counties) but by small margins — not enough to offset GOP wins elsewhere in the state.
Now look at 2008 and 2012, President Barack Obama won Nevada in both campaigns and at the root of those wins were much bigger Democratic margins in Clark. In 2012, for instance, Obama won Nevada fairly comfortably, by about six points, but in Clark he won by a whopping 14 points.
And Obama's 100,000+ vote margin in the county was larger than his vote margin for the state. In other words, he won Nevada because of Clark.
So what was behind that shift? In some ways it's part of a larger trend. Democrats have done increasingly well in what the American Communities Project calls Big City counties since 2000. But in Clark County it's impossible to ignore the rapid growth of the Hispanic population.
Since 2000, the Hispanic population has grown by more than 8 percentage points and when you couple that with the county's remarkable overall growth in that period the impact is multiplied.
As the table shows, when you add the growth factors together, you get a doubling of the Hispanic population in Clark. And that carries big weight throughout the state.
There's nothing the Republicans can do about those numbers, of course. The demographic shifts remaking the country are beyond anyone's grasp to control.
But there is one thing the GOP can control: how it talks to Hispanics and how it tries to win the group's vote. And that's where the GOP has been falling down, badly.
In 2004, then-President George W. Bush lost the Hispanic vote nationally, but only narrowly. He garnered 44 percent of it to John Kerry's 53 percent, a difference of only nine points. In 2012, Republican nominee Mitt Romney lost the Hispanic vote nationally by 44 points. He won 27 percent to Mr. Obama's 71 percent.
When you watch the debate tonight, keep all these numbers in mind. The Republican Party's leadership is aware of all of them as well, and it chose to have this debate in Las Vegas.
So far, much of the Republican campaign dialogue, particularly from frontrunner Donald Trump, has centered on border walls and sending immigrants home.
If the eventual GOP nominee wants dampen the Democrats advantage in Clark County and possibly win Nevada, tonight might be a good time for the candidates to reach out to Hispanic voters in Las Vegas — not to mention other big cities elsewhere.
This article first appeared on NBCNews.com.