The Republican presidential debates have generated abundant analysis and speculation about how the candidates and GOP are faring:

“Can anyone challenge Donald Trump for the anti-Mexican vote?”

“Who will the ‘climate deniers’ rally around?”

“Will Republicans coalesce behind the proposal to repeal the 14th Amendment—as they have around rescinding the Affordable Care Act?”

“Will opposition to same-sex marriage again remain party orthodoxy?”

These may be legitimate questions for cable TV talking heads trying to divine the primaries and for anyone engaging in cocktail party chitchat, but serious Republicans would be much better served by understanding how their candidates and party are perceived by the voting bloc that will dominate America for the next 25 years: the 93 million millennials.

In the process of replacing baby boomers as the most powerful voting bloc in the U.S., this generational cohort will constitute 36 percent of the electorate next year. And there’s much to learn about them—and from them.

For starters, millennials are the most racially diverse generation in U.S. history. In fact, 43 percent are non-white. Most Republican presidential candidates seem to get excited by taking strong stands on old and familiar hot-button Republican issues. This is looking backward. If they are looking forward, GOP strategists and candidates will realize that polarizing rhetoric and old solutions are not where millennials are at. Ignoring them is a blueprint for oblivion.

The days of the baby boomers—my generation—are fast fading. A Pew Research Center report (citing U.S. Census Bureau data) estimates that the millennial generation is projected to surpass the outsized baby boom generation as the nation’s largest living generation.

Issues that might be good for relatively low-turnout Republican primaries will very likely galvanize millennials into a powerful voting bloc for the Democrats. This is bad news for the Grand Old Party, because these young people are unlike their elders in many ways. More than 70 percent of them support the Affordable Care Act. By 2-to-1 margins, they support a path to citizenship for undocumented immigrants who are here without legal status. In the Pew poll, 67 percent support gay marriage equality.

When the 2016 Democratic presidential candidates debated recently, they all supported a path to citizenship for undocumented immigrants, reaffirmed their support for the Affordable Care Act and marriage equality and promised to adopt policies to reduce carbon emissions -- mindful, no doubt, that young adults overwhelmingly support those positions.

And although it seems to have gone largely unnoticed by the Republican candidates and their strategists, the millennial generation is also already reshaping the GOP. In a Gallup survey earlier this year, the percentage of Republicans and Republican-leaning independents who are conservative on both social and economic issues rises steadily with age.

Gallup’s analysis of surveys conducted since the 2012 election shows that the size of the social and economic conservative group is twice as large among Republicans aged 65 and older as it is among those aged 18 to 29. The older voters may determine the identity of the eventual Republican nominee next July in Cleveland, but this will not necessarily be good news in the 2016 general election—and in quadrennial elections to come.

The mature ages of the top two 2016 Democratic presidential candidates notwithstanding, in the last 20 years, Democrats have tailored their party to the aspirations and policy positions of young voters; the Obama campaigns of 2008 and 2012 skillfully managed to get millennials to turn out and vote. And the trend line for Democrats is impressive: In 2004 John Kerry won the 18-to-29-year-old voters (17 percent of the electorate) by nine points. In 2008, Obama won them by a margin of 34 percent, which increased in 2012 to 39 percent.

The poor performance of Republican presidential candidates with young voters was not always the case. Ronald Reagan won 18-to-29-year-olds by more than 20 percentage points in both 1980 and 1984, as did Richard Nixon in 1972, the first election for which baby boomers were eligible to vote in significant numbers.

Millennials are not only the largest generation; they are more progressive than their parents. The Pew Research Center published the results of an ideological survey of over 10,000 Americans and found definitive evidence that millennials are far less conservative (15 percent) than their parents (34 percent) and far more likely to identify as Democrats (50 percent) than Republicans (34 percent).

A survey released in August by the Public Religion Research Institute reported people between the ages of 18 and 29 have more liberal views on same-sex marriage than their parents and grandparents -- regardless of political affiliations or Christian faith. Forty-nine percent of those considering themselves Republicans favor same-sex marriage, including 44 percent of white evangelical millennials, compared to 19 percent of Republican seniors.

Edward Flattau, an environmental newspaper columnist writing for the Huffington Post, notes that poll after poll confirms that the partisan division over climate change is breaking down among millennials, as the perceived risks make a “better safe than sorry" approach ever more attractive. Evangelical millennials tend to acknowledge the climate change threat in contrast to their elders, who constitute one of the last bastions of strident skepticism.

Over the past 100 years generations have tended to vote, for most of their lives, for the party on which they cut their political teeth. The “Greatest Generation” came of age during the FDR presidency and voted the Democratic nominee in every election (except the Eisenhower/Stevenson campaigns) for the next three decades. Same with the boomers, who came of voting age en masse in 1972. Nixon won them overwhelmingly and they voted for every Republican presidential candidate until 1992.

If Republicans don’t change their tune and their tactics, the “wall” Donald Trump says he wants to build won’t be on the U.S.-Mexico border, it will be between the Republican Party and victory in 2016—and for decades to come.