By Sean Trende - July 1, 2013

Politico leads its website Monday with an article pressing the argument that Republican gerrymandering could actually end up hurting the party. By creating safe districts where Republicans have to worry more about losing a primary than losing the general election, the GOP is being pushed rightward, potentially hurting its national prospects.

These types of arguments are nothing new. Neither are the fairly compelling arguments against them.

First, the underlying assumption about the cause of district polarization is wrong. As I’ve suggested before, the natural geographic concentration of the Democratic vote is more responsible for polarized districts than any efforts by Republicans. For that matter, states where Democrats controlled the redistricting process yielded pretty heavily Republican districts as well. Illinois has two evenly matched districts (one represented by a Republican, one by a Democrat), but the remainder of the Republican-leaning districts went for Mitt Romney by healthy margins (even as he lost nationally by four points).

Remember, the primary goal of redistricting isn’t to create safe districts for your party (though that is probably a secondary goal). The primary goal is to place as many supporters of the other party into as few districts as possible, leaving your supporters in a lot of districts that are just partisan enough to fend off general election challenges.

This leads to the second point: If Politico is correct, then Democrats should be in big trouble, because there are more overwhelmingly Democratic districts than there are overwhelmingly Republican ones. The New York Times’ Nate Silver, making a related point, has created the following chart, which shows the cumulative number of districts sorted by Obama’s share of the vote.

Silver writes:

The asymmetry is self-evident. There were 44 Congressional districts in which Mr. Obama won by at least 50 percentage points last year, compared with only eight for Mr. Romney. These hyper-partisan districts are far past the point where a Democratic candidate for Congress could lose under almost any circumstance, so they create wasted votes for Democrats.

Put differently, 68 Republicans -- 29 percent of the caucus -- occupy what we might call heavily Republican districts: districts that voted 15 points more Republican than the country as a whole. Eighty-three Democrats -- 41 percent of the Democratic caucus -- occupy districts that voted 15 points more Democratic than the country as a whole.

If we take a more liberal definition of what constitutes a “safe” district, the parties are basically at parity: 81 percent of Democrats occupy districts that are at least five points more Democratic than the country as a whole, while 81 percent of Republicans hail from districts that are similarly Republican. But the bottom line is that whatever malady is supposedly afflicting Republicans should also be afflicting Democrats, perhaps more so, if gerrymandering were to blame.

This leads to the third, most important point: Contrary to conventional wisdom, moderate districts do not clearly beget moderate candidates. For some good, concrete examples, think of the Senate. The states that are between two points more Republican and two points more Democratic than the country as a whole currently send senators like Tammy Baldwin, Sherrod Brown, Al Franken, Tom Harkin, Ron Johnson, Amy Klobuchar, Harry Reid, Pat Toomey and Mark Udall to the Senate.

None of these senators is going to be mistaken for a moderate anytime soon. The rest tend to be reliable conservative or liberal votes who have the occasional apostasy -- senators like Kelly Ayotte, Bob Casey Jr., Chuck Grassley, Rob Portman, and Marco Rubio. The senators who really fit the bill as moderate tend to be those who manage to get elected in deeply unfriendly territory: Think Joe Manchin and Susan Collins.

As Nolan McCarty has observed, this is a huge problem for the polarization-due-to-gerrymandering hypothesis. The Senate is usually cited as the epicenter of polarization and partisan dysfunction in our country, yet its “lines” have remained unchanged since Hawaii became a state in 1959. McCarty also notes that if you look at the ideology of House members who represent swing constituencies, their ideologies have likewise spread apart over time.

Now I’m not going to claim that there is no relationship between partisan districts and the ideology of incumbents. The relationship between district security and ideology in the House is statistically significant. But it is relatively weak, and as the Senate and “swing district” examples demonstrate, isn’t the primary force driving polarization.

We have an ideologically polarized House and Senate because our country has become politically more polarized. The Grand Ideological Realignment that began in 1932, where we began substituting ideological parties for the old ethnic/sectional parties, has mostly worked its way out. Today, conservatives by and large vote for Republicans, and liberals by and large vote for Democrats. It is now extremely difficult for a Republican to be elected to represent the Upper East Side (as Bill Green did from 1978 through 1993) or for a Democrat to be elected to represent Pascagoula, Miss. (as Gene Taylor did from 1989 through 2011).

The Politico piece has an additional problem. The author seeks to tie this in to the immigration debate, writing:

A look at the numbers shows why there’s more incentive for House Democrats to get behind an immigration bill than Republicans. Nearly two-thirds of Republicans represent districts in which Hispanics make up less than one-tenth of the population, according to the American Community Survey. The number of House Democrats with such few Latinos in their districts? Fewer than one in three.

This is exactly the type of problematic analysis that I’ve been writing about over the course of the past week (with another piece pending). You simply cannot conduct good election analysis by focusing exclusively on the potential effects of a political position on one group, especially when that group is 10 percent of the electorate (up from 9 percent in 2012). In a diverse country, every electoral action tends to have opposite reactions with different groups.

In this case, the reaction isn’t equal, and might even favor Republicans. The GOP’s failure to represent heavily Hispanic districts is probably somewhat pushing Republicans to oppose the immigration bill, which might well injure the party’s prospects with Hispanics (although this is probably overstated).

But polarization is a two-way street, and the Democrats’ underrepresentation in white districts is probably driving them to support an immigration position that is significantly less popular with white (and African-American) voters.

As I mentioned in my last piece, this has played out somewhere between a wash and a movement somewhat in the Republicans’ favor in Arizona, which has quietly gone from being about four points more Republican than the country as a whole in 2004 to being six points more Republican than the country as a whole in 2012. Barack Obama’s share of the vote was almost identical to John Kerry’s, despite growth in the Hispanic share of the electorate and a movement away from Republicans.

Coalitions are like water balloons: You push down on one side, and another side pops up. The actions of the GOP might hurt it with some groups, but good analysis acknowledges that the same is true for Democrats. Good analysis also recognizes that this is distinct from policy, and that what the political effect of a bill is often is separable from what a party ought to do.

Both parties are nearing historic lows in their approval ratings with the American people, although Democrats are faring a touch better than Republicans. Polarization is a boon to neither party. But it’s being driven primarily by shifts in the country, not by gerrymandering.