by Ian Smith July 16, 2015 4:00 PM

There’s no mystery about why Democrats resist enforcing our immigration laws.

A new “sanctuary cities” map from the Center for Immigration Studies goes a long way toward explaining why open-borders Democrats are so addicted to flouting our immigration laws. When you consider the political makeup of the cities, counties, and states where illegal aliens are welcomed, you start to suspect that the liberal elite in San Francisco and elsewhere aren’t interested only in cheap nannies and gardeners. For them, pulling in more illegal aliens is, perhaps first and foremost, about pumping up their political power.

The Census Bureau includes aliens (both legal and illegal) in the statistics used to apportion our 435 congressional districts. This has the perverse effect of helping states with bigger immigrant populations to inflate both their representation in Congress and the number of Electoral College votes they are allotted (the latter is a function of the former). Just through their illegal-alien numbers, the states of New York, New Jersey, California, Florida, and Illinois, which all went for Obama in 2012, received eight additional congressional seats in the last reapportionment, with over half of those gains coming from their sanctuary cities and counties. It’s clear, then, why Democrats resist enforcing our immigration laws: More bodies mean more power.

It is estimated that fully half of America’s 41 million immigrants have settled in just five metropolitan areas: New York City–Newark, Los Angeles, Chicago, Miami, and San Francisco–Oakland. According to data from the Center for Immigration Studies, every one of these cities and their surrounding counties has sanctuary policies of some kind. Considering the illegal-alien pull factor of these policies, which Kate Steinle’s murderer admitted to, it’s unsurprising that the immigrant populations of these sanctuary cities includes many who are here illegally. Data from the Migration Policy Institute show that 3.2 million of the nation’s 11 million illegal aliens reside in just 19 counties that include the sanctuary cities of the deep-blue states listed in the previous paragraph. Furthermore, because these estimates are based on Census Bureau mail-in forms, which some commentators believe illegal aliens are on average less willing to return, they likely undercount the true level of illegal aliens in these counties.

After the 1910 census, when the U.S. population was 92 million, Congress capped the number of House seats at 435. The immigrant population has since exploded, especially after the passage of the Immigration and Nationality Act of 1965, heavily promoted by Ted Kennedy. Today, average representation in the House is around one representative per 700,000. By comparison, the lower chambers in Canada, Britain, France, and Germany have around one representative per 90,000.

It’s not surprising that California flipped from red to blue after the U.S. adopted an open-borders policy.

The immigrants we’ve let in since the late Sixties are largely Hispanic, and ever since the 1980 election, when we started tracking their voting figures, Hispanics have reliably voted heavily Democratic. Considering, then, that California has two of the five main areas immigrants end up settling in (Los Angeles and San Francisco–Oakland), it’s not surprising that the state flipped from red to blue after the U.S. adopted an open-borders policy. (California has just enacted a statewide sanctuary policy, although it is weaker than San Francisco’s.)

But on top of up-ending states politically, open-borders and sanctuary policies also make those states more powerful. Neither San Francisco County nor four of the counties surrounding it (Santa Cruz, Santa Clara, San Mateo, and Contra Costa) enforce Secure Communities, a federal program that requires sheriffs to cooperate with immigration authorities when they’re asked to hold aliens for pickup. Together, these five counties account for over 330,000 illegal aliens, or half a congressional seat — or Electoral College vote. That may not seem like much, but as we know from the Bush–Gore election, one Electoral College vote can determine the outcome of an election. And if those five counties are taken together with Los Angeles County and two of its neighbors, Orange and Riverside Counties, their combined illegal-alien population accounts for almost three congressional seats.

And if you look at the entire illegal-alien populations of the top immigration states, New York, New Jersey, California, Florida, and Illinois (I’ve excluded the Republican stronghold of Texas), together these states are given a full eight additional representatives in Congress. If the Obama administration actually compelled these states to enforce our immigration laws, would they have such outsized representation? More fundamentally, eight Electoral College votes could make a difference in a close election.

Naked self-interest has surrounded our apportionment system ever since it was revised by the Fourteenth Amendment. In a law-review article about the debates over the apportionment clause in that amendment, Patrick Charles, a former analyst with the Immigration Reform Law Institute, describes how Congressman Roscoe Conkling from the big-immigration state of New York lobbied hard for a broader apportionment base because, as Conkling said, the estimated “unnaturalized foreigners” in his state contributed “three Representatives and a fraction of a fourth.”

For the mostly Democratic sanctuary cities, counties, and states to start enforcing our immigration laws, they would have to surrender a sizable amount of power, an unlikely prospect. The GOP could try to pass legislation requiring that the Census Bureau collect information about citizenship and residency status, which Senator David Vitter of Louisiana tried to do in 2009; this would provide a dataset that could be used to remove illegal aliens from the apportionment base. But of course the Democrats would fight it tooth and nail. Unsurprisingly, of the 50 congressional districts covered by the 19 sanctuary counties mentioned above, 47 are held by Democrats. Many of these representatives would surely be put out of work if illegal aliens were removed from the apportionment base and the sanctuary magnet was turned off. But if our immigration laws continue to be evaded, finding sanctuary from open-borders Democrats will only get harder and harder.