An anti-Obama protester yells on a megaphone on Nov. 21 across the street from Del Sol High School in Las Vegas, where President Obama was scheduled to speak on his use of executive authority to relax U.S. immigration policy. (Mike Blake/Reuters)

The influence of ongoing demographic changes on politics is a familiar story. Given current voting patterns, the increasing diversity in the population is likely to work to the advantage of Democrats in future presidential elections. For Republicans, the question is not just how, but whether they can bend the curve.

William Frey of the Brookings Institution explores the future in his newly published book, “Diversity Explosion.” He is one of the nation’s most astute demographers and has long been a reliable guide to the population shifts remaking America and to the longer-term cultural and political implications of those changes.

That the face of America is changing has been evident for many years. But even Frey was surprised “by the sheer scope of racial change that came to light with the 2010 Census.” He is now convinced that “the United States is in the midst of a pivotal period ushering in extraordinary shifts in the nation’s racial demographic makeup.”

Frey cites four broad trends that together will remake the country and shape future politics.

First is the one that is best known: the rapid growth among Hispanics, Asians and, as Frey highlights, multiracial populations. All are expected to double in size over the next 40 years, the result of immigration, higher birth rates among minority populations already here and more interracial marriages.

From left, Lorella Praeli, Chela Praeli and Ligia Jimenez listen to President Obama speak about immigration reform during a visit to Del Sol High School in Las Vegas on Nov. 21. (Kevin Lamarque/Reuters)

Second is the declining growth rates and rapid aging of the white population, the result of both lower birth rates among younger white Americans and the advancing age of the Baby Boom generation.

The combination of the first two changes, Frey notes, will produce generational competition in future decades over resources and governmental priorities, a topic admirably explored in another recent book, “The Next America,” by Paul Taylor, as well as by National Journal’s Ronald Brownstein.

The third broad trend cited by Frey is the continued growth of the black middle class and the migration among black Americans from North to South, reversing the historic South-to-North wave of migration in the 20th century.

Fourth is the fact that, by later in this century, there will be no majority demographic group in the United States.

The impact of demographic changes and tensions among the races are evident everywhere.

President Obama’s recent executive actions on immigration, shielding millions from deportation, has intensified the debate over immigration policy and highlights the cultural gulf between older, whiter Americans and a rising younger generation that has grown up with — and grown more comfortable with — racial diversity.

Obama’s victories in the presidential elections of 2008 and 2012 speak to racial progress over the past half century, as well as to the power of minorities — new and old — to effect election outcomes.

The protests in Ferguson, Mo., this past week, however, are a reminder of long-standing racial divisions that have not been overcome and the gap between whites and blacks as they view society.

Frey strikes a hopeful note about the unease among some Americans about growing racial diversity. Over time, he argues, those “will almost certainly dissipate” as the minority populations continue to spread to different regions and into different communities and the assimilation process takes place.

That is likely to take time, however. The past two presidential elections have underscored that politically, this is still a nation divided. In 2012, for every 10 votes Mitt Romney won, nine came from white voters. Obama, meanwhile, won eight of every 10 votes cast by a minority voter. Frey believes that is unsustainable over time.

Those elections showed the powerful impact that a rising and energized minority population can have on presidential campaigns. By Frey’s analysis, minority voters provided the key to victory for Obama in Ohio, Pennsylvania, Florida, Nevada, New Mexico, Virginia and Colorado in both elections. Frey adds Indiana to the list of states for 2008 and Wisconsin to the list for 2012.

Despite talk among some Republicans that their big problem in 2012 was a fall-off among white voters, the GOP cannot rely on a mostly whites-only coalition, as many in the party have argued. But Frey also notes that a strategy based on massive efforts by Democrats to turn out minority voters, while losing whites by historically large margins, “is not a viable long-term strategy” for Obama’s party.

For now, changing demographics continue to reshape the electoral map to the disadvantage of Republicans, offering Democrats opportunities to compete in states that once were reliably Republican. That’s already happened in places such as Colorado, New Mexico and Nevada. In the future, Democrats could become more competitive presidentially in states like Arizona because of the Hispanic population, or Georgia because of the growing African American population.

Demographic projections put Texas on that future list as well, given that the state is projected to have a minority-majority electorate as soon as the 2020 presidential election. But as Texas Gov.-elect Greg Abbott showed this fall, if a Republican candidate can win a substantial share of the Hispanic vote — he got about 44 percent, according to exit polls — the Democrats’ hopes of turning Texas blue become more challenging.

“There has been a piece of fiction promoted by [Democrats and their allies],” Abbott told me in a recent interview. “We disproved that thesis this election.”

Abbott may be correct about Texas. His predecessors as governor — Rick Perry and George W. Bush — also were effective in winning Hispanic votes. If they could do nationally what they’ve done in Texas, it would change assumptions about the future. Bush did that in 2004, but John McCain and Mitt Romney failed badly in the past two elections. In an interview, Frey said, “In the longer term, they absolutely have to be much more open to minorities and make a much more serious attempt to deal with Hispanics.”

Meanwhile, there is a shorter-term opportunity for Republicans. Demographic changes have put increased focus on a group of states that once were far more reliably Republican, particularly those in the Sun Belt and the intermountain West, states like Florida, North Carolina, Virginia, Nevada, New Mexico and Colorado. Obama won them all in 2008 and all but North Carolina in 2012, thanks to rising minority participation.

Frey points to six northern states — Ohio, Pennsylvania, Wisconsin, Michigan, Minnesota and Iowa — whose demographic makeup may be better for Republicans, although the GOP has struggled in most of them in recent presidential elections Pennsylvania, Michigan Wisconsin and Minnesota have been reliably Democratic. Ohio and Iowa have been more competitive.

Their populations are older and whiter than those in the newer battlegrounds of the Sun Belt, and their electorates are composed of more white, blue-collar voters. Frey suggests that this northern heartland could become “open to Republican messages tailored to older baby boomers and blue-collar workers.”

Overall, coming demographic changes provide more advantages to Democrats than Republicans. But that assume static politics, which Republicans can’t afford and Democrats shouldn’t assume. Frey writes that it will be incumbent on both parties to “cross the racial divide” in coming years. As he puts it: “Each party has to find ways to compete for both younger and older voting blocs in future presidential elections.”