Winning feels great. But the best don't settle and assume they've figured out how to succeed forever. New England Patriots coach Bill Belichick, upon winning the Super Bowl this month, declared that despite the great feeling of winning, he was concerned that he was already "five weeks behind" for the next season. Champions are always looking to the horizon, trying to figure out how to succeed again, rather than spending too much time dancing in the end zone.

Republicans hold an incredible number of levers of power in American government, from the federal to local level. With Democrats licking their wounds and trying to figure out a way forward — tack hard left? Move to the center? Print more "Nasty Woman" shirts? — the GOP is feeling pretty great about itself.

But pride comes before the fall, and as Republicans pat themselves on the back for a job well done, the harsh reality remains that the Right has a lot of work to do when it comes to winning over the next generation and shoring up support for conservative ideas down the road. Intergenerational friction in our nation's modern politics has finally created enough heat to get noticed, but slow-burning trends around demography and culture continue to shape the future of our politics.

Age did not always correlate with partisanship in the way it does today. Elections not long ago had almost zero generation gap, and the adage that people always become more conservative with age doesn't hold up in the data. (Some generations — like the Baby Boomers — move a lot politically over their lifetimes, while others — like Gen X — have moved very little.)

When Republicans lost voters under age 30 by a two-to-one margin in the 2008 election, it was chalked up to the once-in-a-lifetime candidacy of Barack Obama. When Obama trounced Romney with the under-30s four years ago, the same was said, along with promises that these young voters would surely one day come to their senses and swing back rightward as they aged.

So it should give Republicans little comfort that President Trump won only 36 percent of young voters in an election where he did not have to face Obama on the ballot. (Even Romney was able to win 37 percent.) Against Hillary Clinton, an opponent who could not energize millennials whatsoever in her own primary, Trump could barely muster one-third.

Even more troubling for Republicans is that the oldest edge of the millennial generation has now reached their mid-30s, and sure enough, they are not swinging rightward. Trump won only 41 percent of voters in the 30 to 44-year-old range, barely better than with the younger millennials and four points worse than either McCain or Romney did with the same age group against a more formidable Obama campaign.

Younger voters are not being won to the GOP. And as these voters get older, they aren't organically making the switch. If conservatives don't make their case, the thrill of short-term victory will eventually give way to the slowly-rising tide of a generation unconvinced that conservative values and free markets lead to peace and prosperity.

To be sure, many argue that young voters don't matter. Trump won without them, so who needs them? Doing well with older voters (and ignoring younger voters) was a serious piece of Trump's path to victory last year. Of the six states that flipped from Obama to Trump (Iowa, Michigan, Wisconsin, Pennsylvania, Florida, Ohio), all four are in the top ten states for highest average median age. In the short run, Trump was able to realign the political map by tapping into an older, whiter electorate that had was loosely adhered to the Democratic Party and was ripe for peeling away.

But losing young and emerging voter groups plants seeds that are devastating in the long term. The youngest states in the U.S. are not all "blue" states and include some very reliably "red" places like Utah, Texas and Georgia. However, these states broke much less heavily for Trump than they broke for Romney four years earlier.

Take Texas, where Trump won by only nine points. (In 2012, Romney won Texas by 16.) Democrats have long savored the idea of "turning Texas blue," though Republicans have dismissed the notion in the wake of Wendy Davis' failed gubernatorial bid. But if our big Lone Star State electoral vote prize is suddenly only being won by single-digits, that should signal danger ahead to those taking the long view.

This is not to say all is lost. For all that Trump has shown great weakness among the millennial generation, there are elements of Trumpism that could potentially resonate with this generation, if he is able to deliver on promises like more robust economic growth and keeping America safe. That we now have a Republican president who openly embraces the LGBT community is a positive step, and Trump's rhetoric about putting power back in the hands of the people is something that ought to resonate with a generation accustomed to decentralization and customization.

It is notable that of the half of voters under age 30 who say they watched at least the highlights of Trump's inaugural address, 36 percent say it made them feel more hopeful about the future, while 31 percent said it made them feel fearful. There is lots of work to be done, but nothing is impossible.

But when feeling quite satisfied with themselves, parties always miss the threats that face them. Democrats were pleased with their success in 2012 and ignored the warnings of some that their party was in jeopardy of losing the white working class. Republicans should not fall into the same trap. Demographic and cultural shifts continue to be slow-burning trends, even as Trump galvanized a mostly older voting bloc against some of those shifts. To pretend one election has solved the GOP's problems with young voters is foolish, especially when this election may have exacerbated the problems over the long term.

Winning feels great, and everybody loves a winner. But the very best figure out what's coming next and don't assume they've got the winning formula forever.

Republicans had better be ready for the slowly-rising millennial wave that is heading their way.

Kristen Soltis Anderson is a columnist for The Washington Examiner and author of "The Selfie Vote."