(Jewel Samad/AFP/Getty Images)

The writer, White House press secretary from 2001 to 2003, was a co-chairman of the Republican National Committee’s review of the party’s defeat in the 2012 presidential election.

America is a tale of two electorates. On Tuesday, the GOP won big. The next election is likely to involve a very different group of voters, and Republicans need to realize that what worked in 2014 won’t work in 2016. If Republicans aren’t wise, this victory could be short-lived.

The biggest difference between the electorate of 2014 and the one coming in 2016 is who didn’t vote Tuesday. National turnout data are not available yet, but assuming turnout was similar to the 2010 midterms, roughly 90 million Americans voted Tuesday; two years ago, in the last presidential election, about 129 million people turned out. Who are the missing 39 million voters? They’re mostly from the Democratic base, who typically don’t vote in midterms but reliably show up for presidential contests.

According to exit polls, this year’s electorate was 12 percent African American, 8 percent Hispanic and 13 percent between age 18 and 29. On Tuesday, these groups voted Democratic by 89 percent, 63 percent and 54 percent, respectively.

If the presidential election of 2012 is any guide to 2016, and it’s certainly a good basis for planning, here is what Republicans can look forward to: The African American vote will be 13 percent of the electorate, up one percentage point from 2014. The Hispanic vote is projected to be 11 percent, up three points from 2014. And the youth vote will be about 19 percent, up six points from 2014.

In other words, the Democrats are coming.

Republicans, who have won the popular vote in just one presidential election since 1992, need to do things differently if they want to win the White House again. It’s one thing to win a rejection election against the party in charge; it’s another to prove to the voters that you have ideas and are ready to govern. While U.S. demographic changes are important, nothing attracts voters more than an appealing ideology.

The first thing Republicans need is a specific and positive agenda. Everyone knows the GOP stands against President Obama, and it was rewarded for that Tuesday. But to win in a presidential year, GOP presidential candidates, who will define the image of the party, need to be the candidates with ideas. Growth-oriented reform of the individual tax code, corporate tax reform, a replacement for Obamacare, anti-poverty measures that work, exporting energy, a military buildup — all of these areas can be part of a campaign that gives voters a reason to vote for someone, rather than against someone else.

Along the way, Republicans must communicate and act in a more open and inclusive manner. Statements about “self-deportation” for illegal immigrants, for example, alienate voters who would otherwise be open to Republican ideas. It is high time for the GOP to move forward on immigration reform. Immigration isn’t the only issue that Hispanics care about, but a willingness to move forward on reform will be instrumental in letting immigrants know they are important to and welcome in the party. A compromise needs to be found that respects the rule of law while allowing people who came to the United States seeking opportunity to find it.

George W. Bush, who supported immigration reform, won 44 percent of the Hispanic vote in 2004. Mitt Romney received 27 percent. If Republicans don’t win at least roughly 35 percent of the Hispanic vote, it’s hard to imagine them winning the White House again.

Republicans made inroads with young voters Tuesday, losing them by 9 points compared with 23 points in 2012, but not because 18-to-29-year-olds like Republicans. It’s because they turned away from Democrats. These voters are increasingly up for grabs.

One way to win over more young voters is to stop scaring them away. Interestingly, gay rights have become somewhat of a gateway issue for young people. Younger Republicans are increasingly open to gay marriage, presenting the GOP with a generational split. Even if this split remains, the party needs to find points of consensus, such as ending workplace discrimination against gays. People simply won’t vote for you if they think you don’t like them. The GOP needs to modernize its appeal or too many young voters will roll their eyes when they see a Republican presidential candidate coming.

By my count, approximately a dozen Republicans are considering running for president, including six governors, a former governor, three senators, a former senator and one physician. I hope I didn’t leave anyone out.

As the primary proceeds, the candidates need to keep their eyes on the prize. A conservative ideology will be a winning ideology if it’s presented in a manner that unifies and uplifts. Competition is healthy in all things, and that includes presidential politics. There is nothing wrong with a good ideological battle to vet and settle intra-party differences. But if Republicans engage in that fight in a manner that alienates large portions of a general electorate that will be out in full force in 2016, this week’s victory is sure to be fleeting.

It’s good to block Obama. It’s better to lead America in a new direction.