Citified America and other facts of life. Deal with it.

Presidential candidate Rick Santorum bragged about his appeal to small-town, rural America last week, even pitting himself again urbanites. There’s nothing wrong with that, of course. We all have our audience.

But if Mr. Santorum really wants to be president, then the math of small-town America is working against him. Like the rest of world’s population, which became mostly urbanized in the last decade, most Americans by far live in urban areas, according to the Census Bureau. That’s not news; that’s been the case for decades.

The most recent figures from the Census Bureau show that 79 percent of Americans live in urban areas. (In 1790, the days of the founding fathers, only 5.1 percent did.) The trend toward urbanization has slowed a little, but it continues.

So I find Mr. Santorum’s souring on cities a little confusing. Even an electoral map of last week’s Illinois Republican primary shows where most people live. He won the greater number of counties in the state, but thanks to Chicagoland, Peoria and Springfield, not the greatest number of voters. In fact, Mitt Romney won the state by almost 12 percentage points–a difference of more than 100,000 votes out of fewer than one million cast.

Mr. Santorum’s emphasis on values taps into a certain nostalgia and romanticism about small-town life. I know its charms firsthand. My earliest memories are of New York City, but the moves of my life since childhood have taken me to ever-smaller places. The town I call home now boasts a population of about 63,000, and sizable swaths of farmland still exist inside the city limits (although housing and commercial developments are gradually erasing them). Emotionally, the intersection of Norman Rockwell Boulevard and Disneyfied-Main-Street is a very inviting place.

But that’s not where most of us live. Not anymore. So Mr. Santorum or anyone else who wants to be president must deal with the fact of cities. Like it or not.

Mr. Santorum’s dilemma prompted me to think about other assumptions about American practices and ideas that don’t really match reality, at least anymore. A sampling:

• Marriage rates are decreasing. In 1990, 9.8 people out of a thousand were married; in 2009, the latest figure available, the rate was 6.8—a 30 percent drop.
• But divorce rates are decreasing too, from 6.1 per 1,000 to 3.8 in 2009.
• These days, most children born to women under 30 years old are born out of wedlock.
• The conventional wisdom used to be that couples who lived together without marriage were more likely to get divorced. Not anymore—not if they’re engaged when they are cohabiting.
• Man as the breadwinner? Going, going … Present trends suggest that “by the next generation, more families will be supported by women than by men,” writes Liza Mundy in a new book excerpted in Time magazine (March 26). She continues: “Not since women entered the workforce by the millions after World War II has America witnessed economic change on this scale. Some of this is driven by the dramatic rise in single-parent families, but it is increasingly true in two-earner families as well. In 2009, the most recent year for which U.S. Bureau of Labor Statistics figures are available, nearly 4 in 10 working wives outearned their husbands–an increase of more than 50% from 20 years before.”

You can probably think of other stereotypes or dreamscapes that don’t fit reality anymore. (Feel free to add them in comments after this post.)

We might love or loathe any particular change, but that’s not the point. The point is: Certain facts reflect the current American landscape, and we must figure out how to navigate it rather than deny it or simply throw brickbats at it. Like it or not.