I’d been playing with an idea lately, only to find that Genghis Khan acted on it 800 years ago.

Genghis began to solidify his political control over the Mongol tribes by changing the way food was provided. Altering tradition, he distributed the take from the hunt himself instead of allowing aristocratic families to control the allocation of food.

The contemporary analog is evident in the work of many of the world’s most successful political parties, which these days provide real social services, not just a steady diet of ideology and propaganda.

Hamas just won nearly three-quarters of the vote in the West Bank city of Nablus, leaving the late Yasir Arafat’s Fatah in the dust. When it isn’t blowing up Israeli buses and pizza parlors, Hamas runs schools, orphanages, healthcare clinics, soup kitchens and sports leagues — services the Palestinian Authority itself often fails to provide. Scholars argue that these programs explain much of the movement’s popularity.

Across the line in Israel, Shas, a party consisting mainly of Jews from the Middle East and North Africa, has quadrupled its support in the past 20 years. In addition to its ethnic appeal, Shas educates some 40,000 students each day, providing free transportation, subsidized meals and all-day child care for hard-pressed working parents. In addition, Shas offers rehabilitation for delinquent kids along with jobs and housing programs.

Of course, in earlier incarnations, American urban machines were also social-service providers, offering their followers jobs, shelter, food and community when they were in need. As Democrats became more successful in advocating for government provision of these services, the role of the party as provider withered, along with the loyalty of some constituents.

Two other quasi-political institutions in America work similarly. In addition to giving workers a voice, labor unions have offered members education, training, insurance and a host of other direct benefits. But labor too has been victimized by its success. When government or business is compelled to offer the same service, the unique role of the union as provider to its members fades.

Conservative mega-churches have also grown partly by being service providers. The Economist recently reported on Willow Creek Community Church, which offers food courts, basketball courts, day-care centers, Weight Watchers groups and motorcycle clubs as well as counseling to deal with every conceivable ill. Such mega-churches have been particularly successful in exurban areas, where other service providers have been unable to keep pace with the rapid population growth. These mega-churches often provide a locus of institutional activity for Republicans.

None of this is to deny the appeal of the ideas advocated by Hamas, Shas, the labor movement or the mega-churches; providing services is not their only recruiting tool. But it is not unimportant. Many of the fastest growing parties and political institutions in the world are finding ways to cement the loyalty of their followers by offering services.

Loyalty is based less on agreement than on reciprocity. People offer allegiance to individuals and institutions that have given something to them. Who would betray the Khan who gave your family its food, the political boss who got you your job, the party that provided a school for your child, the union that trained you or the church that cares for your children?

As Democrats ponder our future, we would do well to keep this lesson in mind. While offering a compelling platform and strong, capable leaders is absolutely necessary, it may not be sufficient. Unlike Genghis, we won’t be bringing the days kill to the door, but we should rethink what our party can do directly for people and reevaluate what needs it can meet in addition to political expression.

Mellman is president of The Mellman Group and has worked for Democratic candidates and causes since 1982, including Sen. John Kerry (D-Mass.) in 2004.