Today's Nevada caucus will foreshadow the future of American politics well beyond 2020.Why it matters: The U.S. is in the midst of a demographic transformation, and the country's future looks a lot like Nevada's present. Today's results, in addition to shaping the 2020 race, will help tell us where politics is headed in a rapidly changing country.The U.S. in 2045 will look a lot like Nevada in 2020.The U.S. is on track to become minority white by 2045. Nevada is one of just 4 states that are already there.Hispanic people are expected to make up 25% of the American population by 2045. They're 29% of Nevada's population today.Immigration will likely be the backbone of the U.S.' future population growth, and will likely hit record levels by 2045. Today, immigrants' share of the Nevada population is the 5th largest of any state.The vast majority of Nevadans live in urban areas, just as 89% of Americans are projected to by 2050, according to UN data. At 10% of the population, Nevada's black voting bloc is also significant. The U.S. will be 13% black in 2045. In the shorter term, 2020 will be the first general election in which eligible Hispanic voters outnumber eligible black eligible voters, and most of those voters are Democrats.So the votes of Nevada's large Hispanic population likely will signal where the Hispanic vote is headed in bigger primary states such as Texas and California, and may be the deciding factor in Democrats' ideological identity crisis.And if the caucus sees high turnout, as Hispanic Federation senior vice president Brent Wilkes predicts, "that enthusiasm will carry over into other states as well," he said. "Nevada will provide the first glimpse of how the candidates will fare in much of real America — especially with the highly diverse Democratic base," Brookings Institution's William Frey said. Where it stands: Heading into the caucus, Sen. Bernie Sanders is at the top of the RealClearPolitics polling average in Nevada with 30%; and polls also show him winning over Hispanic votersrs. Former Vice President Joe Biden in second (16.7%) followed by former South Bend, Ind., Mayor Pete Butigieg (14%) and Sen. Elizabeth Warren (13.7%). Yes, but: 7% of Nevada's population is undocumented — more than any other state and more than the national share, according to Pew. "The connections to the challenges of being undocumented might perhaps resonate in a way in Nevada more so than other states around the country among Hispanic voters." Mark Lopez, director of global migration and demography research at Pew Research Center The bottom line: Nevada's caucus results will tell us how demographic shifts are likely to change the balance of political power nationwide.