In the heat of campaign season, political partisans often miss the forest for the trees. Every comment about "bayonets" or "binders full of women" seems to take on tremendous significance, even though it will be largely forgotten in a few months.

But leaders in the Republican Party need to start thinking about the future, not just about 2018 and 2020, but beyond that.

A new poll from McClatchy shows the Republican nominee, Donald Trump, winning only 9 percent of the under-30 vote. That puts him in fourth place, behind Hillary Clinton (41 percent), Libertarian Gary Johnson (23 percent) and Green Party nominee Jill Stein (16 percent).

This should alarm Republicans, and prompt them to prepare a 2016 post-game that looks very different from what we are seeing now. Whatever segment of the party survives this election, and even if Trump wins, the rebranding effort for the future will have to be much more serious and sincere than it was after the 2012 defeat.

Younger people are always going to harbor more left-wing sympathies than the rest of the population. This has been so for decades. It is part-and-parcel with the care-free life of the college student, life before parenthood, and life before earning a paycheck and seeing how much is taken out of one's paycheck in taxes. The most fancifully idealist notions, such as Bernie Sanders' socialism, still, at that age seems plausible.

Even in the revolutionary election of 1994, Republicans only just broke even among under-30 voters. Still, it is not some iron law of nature that voters will move right as they mature. There is no guarantee that life experience will warm the young to the GOP if Republicans continue to alienate them so effectively.

Republicans need to start thinking about just how profoundly unattractive the party has become to a lot of young people. It genuinely risks losing an entire generation. This doesn't require an abandonment of principle, but does mean cleaning up the party image, changing the message and revisiting some legislative ideas.

The relatively strong support for Gary Johnson in the McClatchy poll shows that the more libertarian elements of the GOP platform represent a good starting point. On social issues, the picture is more nuanced. Polls tend to show that younger voters (and younger women, in particular) are less inclined to favor abortion than are their elders. They are also far more likely to support same-sex marriage, an issue which the courts have perhaps taken off the political table.

Another policy where Republicans have a problem with the young is immigration. It's not necessarily true that younger voters want "amnesty" or believe in "open borders." But they don't like hostility toward immigrants of the sort apparent in the rhetoric of some Republican candidates and campaigners. If Republicans are as welcoming of immigrants as Ronald Reagan was, then there is ample room for a policy that insists on orderly and legal immigration. This should include the aggressive removal of criminal immigrants, a common-sense policy to which even the Obama administration has been forced to pay lip service.

Elections are not just about issue positions. They are decided at least as much on questions of tone and candidate personality and quality. Voters are generally unlikely to be persuaded by facts and logic; they will believe what is told to them by people they like. This is an area where both Presidents Obama and Reagan have excelled.

Witness, for example, how an optimistic, jovial and well-liked President Reagan managed to sell the public on entirely new paradigms about both the Cold War and taxes. Witness also the transformation on same-sex marriage that Obama was able to bring about almost singlehandedly, especially among black voters, by simply reversing his own long-stated position on the issue.

The single most important change Republicans need to make is something that the current vice presidential nominee, Mike Pence, has been preaching for more than a decade. "I am conservative," he has said throughout his political career, "but I'm not angry about it." Conservative principles are, at heart, about broad human prosperity and good government. They remain a coherent and consistent body of thought that can appeal to the young and idealistic, just as they did before. And they can be sold by pleasant and likeable candidates.

Although it would be sanguine to believe that majorities of young voters will embrace conservatism, Republicans can make themselves competitive among those whose budding careers and young lives have been retarded by the stagnation of the Obama years.

In an era of exponential technology growth, people have learned that things can always be done better, and that outdated and outmoded ways of doing things can be safely replaced by newer and better ones. This zeitgeist recommends the replacement of the bad-tempered, grumpy, pessimistic, get-off-my-lawn Republicanism still practiced by too many in the GOP. The party still has a young and strong bench even now, and on it are candidates who can project something much more attractive for the future.