Each of the two major parties enjoys overwhelming advantages with certain demographic groups, and equally stark disadvantages with others. The Washington Post characterizes the divide this way:

Results from November’s midterm elections have exposed a deepening political divide between cities on the coasts and the less-dense areas in the middle of the country.

The Republican Party’s big gains in the House came largely from districts that were older, less [racially] diverse and less educated than the nation as a whole. Democrats kept their big majorities in the cities.

The Post story notes that “Democrats remained strong in areas with the party’s core of minorities and higher-educated whites” but suffered overwhelming setbacks among white working-class voters. “Exit polls,” it pointed out, “showed that Democrats lost white voters without a college degree — one way to measure blue-collar voters — by almost 30 percentage points in House races.”

The Post is on to something here beyond the long-overdue acknowledgment that the Republican party is not a wholly owned subsidiary of nefarious corporations. Congressional districts with heavy concentrations of two demographic groups — racial minorities (especially those who have low incomes or have not finished high school) and people who have earned post-graduate degrees — elect liberals almost 100 percent of the time, sending politicians such as Nancy Pelosi, Henry Waxman, Charlie Rangel, John Lewis, Barbara Lee, and Barney Frank to congressional swearing-in ceremonies.

But a review of Census Bureau data suggests that there may be another way to look at the divide. The GOP’s political advantage appears to correlate with the number of military veterans in a district. Here are some data to contemplate:

According to the Census Bureau, there are approximately 23.4 million military veterans in America. The average congressional district is home to about 53,700 of them, slightly more than 10 percent of its adult population. Of course, there is no such thing as an “average” district. In 20 districts the veteran population exceeds 15 percent of adults while in 25 others it falls below 5 percent.

In delivering the November 2 shellacking, Republicans won 45 seats, the majority of their gains, in the 218 districts with the most veterans. Most of these pick-ups, moreover, required a Republican challenger to defeat a Democratic incumbent.

The GOP now controls over three-quarters of these seats (164, by my count). To put this in perspective, the GOP will control 55 percent of all House seats when the new Congress convenes in January.

The attrition rate for Democrats representing these districts was nothing short of astounding. Show me a Democrat seeking to hold on to a district with large concentrations of veterans and I’ll show you a Republican pick-up opportunity. In fact, the GOP won nearly 50 percent of such seats, 47 out of 99, while Democratic challengers picked up just two of the 119 GOP seats in play.

Election Day was a yawner in districts with comparatively few veterans. In the 100 districts with the fewest veterans, Democrats lost but three seats while gaining back one.

What are we to make of this? For one thing, the emerging concern among conservatives that supporters of the Tea Party movement will back massive cuts in national-security spending seems misplaced. After all, the vast majority of House GOP freshmen — at least 20 of whom are veterans themselves — will return home each weekend to districts chock-full of former Marine drill sergeants, Navy fighter pilots, and Army tank commanders. It is safe to assume that these constituents won’t look kindly on lawmakers who propose to gut our armed services, especially in a time of war.

Mike Franc is a senior fellow at The Heritage Foundation.