THE Republican Party has lost the popular vote in five of the last six presidential elections. It just failed to unseat a president presiding over one of the longest stretches of mass unemployment since the Great Depression. In a year when the Senate map offered them numerous opportunities, the Republicans managed to lose two seats instead.

In part, these failures can be attributed to the country’s changing demographics. Reliable Republican constituencies — whites, married couples and churchgoers — are shrinking as a share of the electorate. Democratic-leaning constituencies — minorities, recent immigrants, the unmarried and unchurched — are growing, and voting in larger numbers than in the past.

But Republicans are also losing because today’s economic landscape is very different than in the days of Ronald Reagan’s landslides. The problems that middle-class Americans faced in the late 1970s are not the problems of today. Health care now takes a bigger bite than income taxes out of many paychecks. Wage stagnation is a bigger threat to blue-collar workers than inflation. Middle-income parents worry more about the cost of college than the crime rate. Americans are more likely to fret about Washington’s coziness with big business than about big government alone.

Both shifts, demographic and economic, must be addressed if Republicans are to find a way back to the majority. But the temptation for the party’s elites will be to fasten on the demographic explanation, because playing identity politics seems far less painful than overhauling the Republican economic message.