Did the legislature gerrymander Matheson’s district in 2001?

It’s often said that the Utah legislature tried to gerrymander Utah’s second district (Matheson’s) in 2001. By moving Republicans into the district and Democrats out of it, the story goes, the legislature hoped to force Rep. Matheson out of office.

I don’t know whether that was their intent. I wouldn’t be surprised if it was. But looking at the data, we can see whether that was the effect. From the data, it’s difficult to say whether the legislature actually made his district more Republican back in 2001.

The usual narrative about Matheson’s district

After the 2000 Census, the Utah legislature needed to adjust district boundaries to ensure that each district would have equal population. Of three U.S. House districts, the first and third were represented by Republicans (Jim Hanson and Chris Cannon). The second district was represented by a Democrat, Jim Matheson, first elected in 2000. Relative to the first and third districts, Matheson’s second district had become slightly underpopulated. It needed around 42,000 more voters to remain in balance.

The Utah legislature could have made minor adjustments to the district boundaries to correct this slight population imbalance. Had they done so, then most Utahns would have been able to continue being represented by their current representative.

Instead, the legislature decided to completely redraw the lines. Rather than move 40,000-50,000 voters from the first and third districts into the second, the legislature moved 684,000 Utahns into different districts. Many voters found themselves moved from the 2nd to the 1st district, or from the 3rd to the 2nd, or whatever the case may be. You can examine the maps below to see just how drastic this change was. The mostly urban second district (dark blue) suddenly covered a large chunk of the state. (Click either image to enlarge.)

Even Republicans perceived this as an unfair attack on Matheson. The conservative Wall Street Journal called this a “scam” to defeat Matheson, one likely to produce “effective disenfranchisement.” The WSJ went on to quote Ronald Reagan’s 1989 warning about the “conflict of interest” legislators have in drawing districts, accusing Utah’s legislators of ignoring Reagan’s “sensible voice.”¹

The Salt Lake Tribune reported criticism from two of Utah’s prominent elected Republicans: “Senator Robert Bennett (R-UT) called it one of the worst examples of political gerrymandering he had ever seen. Republican Congressman Jim Hansen, whose district [Utah’s first] was made less Republican as a result of gerrymandering, criticized the redistricting process, saying that ‘if there was ever an argument for letting someone other than the legislature do redistricting, this is one.'”²

Most criticism focused on Matheson’s new district. And, indeed, he struggled to win reelection under the new map. In 2000, his first race, he had won by 56%-41% in the 1990s-era district. But in 2002, using the new map, Matheson won by only 1,641 votes in a 49%-49% near-tie.

If the story ended there, we’d probably conclude that there was an ugly partisan gerrymander. But the story doesn’t end there. By 2004, Matheson had recovered. And in 2006 and 2008, he won more votes (in the “gerrymandered” district) than he had won back in 2000 (under the old map). The figure below shows all Matheson’s election results from 2000 on. So was he really gerrymandered, or not?

Was this really a gerrymander?

After taking a closer look, it’s not clear to me that the second district was really gerrymandered. It’s true that 2002 was a rough year for Matheson. But I cannot say for sure whether gerrymandering is to blame.

First, let’s define “gerrymander.” The term usually refers to an intentional effort to change a district’s partisan makeup. When people say that Matheson’s district was gerrymandered, they usually mean that the legislature moved Republicans into the district and Democrats out of it. I’m using that definition of “gerrymander” in this post.

Let’s look at the evidence. The easiest way to spot a gerrymander is probably to look at how each district voted for president each year. If you look at Congressional election results, the numbers will be thrown off since each district is voting on different candidates, so you’re comparing apples to oranges. But if you look at presidential election results, you’re comparing apples to apples when you compare one district to the next.

Obviously, each district’s presidential votes will change a little bit each year. For example, if we compare 1996 to 1992, we find that all three districts moved a bit toward the Democratic column. That makes sense; Clinton’s vote nationally was higher in 1996 than in 1992, so we should expect all of Utah’s districts to move in the same direction. Take a look at the table below. Pay special attention to the right-most column.³

This next table (below) gives only the “difference” column. The first column is the difference in the GOP’s vote share between 1996 and 1992, copied from the previous table. In the absence of redistricting, we would expect all three districts to move together every four years. Sure enough, they all move somewhat to the left in 1996, then to the right in 2000, then to the left in 2008.

I left the “2004 vs 2000” column blank. That’s the most important column, since redistricting happened between 2000 and 2004. After the 2001 redistricting, everybody was saying that the legislature had moved Republicans in and Democrats out of Matheson’s second district. To compensate, they would have needed to do the opposite in the first and third districts.

If Matheson’s district was gerrymandered in 2001, we should see the districts moving in opposite directions in 2004. Matheson’s district should move to the right relative to 2000, and the other two districts (which absorbed Democrats from the old district 2) should move to the left. Here’s the data:

We see that district 2 did, in fact, move further to the right than the other districts during this period. Nationwide, Bush’s vote share rose by 1.5 percentage points between 2000 and 2004. The fact that his share fell in district 1 is evidence that Democrats were moved from district 2 to district 1 in 2001.

Note that the difference between districts 1 and 2 in “2004 vs 2000” is 6.9. (That is, +5.0-(-1.9)=6.9.) At most, then, we would estimate that redistricting in 2001 caused a 6.9 percentage point divergence between districts 1 and 2. (Of course, we’re ignoring district 3 entirely, where the divergence is much smaller.) So at most, redistricting caused Matheson’s district to be 6.9 percentage points more Republican than it would otherwise have been under the old map.

We need to be careful not to make too much of these numbers, though. Consider some important caveats.

First, district 1 moved more to the right in “2000 vs 1996” than either other district. Even without redistricting, we would expect a correction in “2004 vs 2000.” That’s just the nature of statistical phenomena; when there’s a sharp change in one period, things tend to revert back in the next period. (This is called “regression (or reversion) to the mean.”) So in district 1, the +9.5 movement between 1996 and 2000 may have foreshadowed to the modest -1.9 reversal between 2000 and 2004.

Second, the difference between districts 1 and 2 in “2004 vs 2000” is 6.9, as noted above. But let’s put this 6.9 divergence in context. The divergence between districts 1 and 3 in “2000 vs 1996,” when there was not any redistricting, is even larger: 7.4. If a divergence of 7.4 points can happen in the absence of redistricting, then we shouldn’t make too much of a smaller divergence of 6.9 points that happens after redistricting. Simply put, the 6.9 point divergence between districts 1 and 2 might just be within the margin of error.

So maybe Matheson’s district was gerrymandered in a partisan way causing, at most, a 6.9 percentage point shift toward the GOP. But maybe this shift would have happened anyway; it might be within the margin of error.

The evidence isn’t strong enough to say for sure whether redistricting had the effect of making Matheson’s district any more Republican.

So why was 2002 a tough election for Matheson?

For the sake of argument, let’s assume Matheson wasn’t gerrymandered at all. Then why did he almost lose in 2002? Isn’t his poor performance in 2002 sufficient evidence of a gerrymander?

Not quite. As a Democrat running in a majority-Republican district, he needs a personal connection with voters if he wishes to persuade them to cross party lines. With the new map, he had only one year to form that personal connection with lots of new voters who were suddenly placed in his district. Even if his district wasn’t any more Republican in 2002 than in 2000, the influx of unfamiliar voters would have made 2002 a tough year for Matheson.

By looking at the graph given at the beginning of this post, you can see that his electoral margins got better and better in 2004, 2006, and 2008. And these elections were not against stooges. In fact, the challenger in 2004 was the same challenger who almost beat him in 2002.

So maybe the legislature didn’t make Matheson’s district any more Republican. It did, however, take Republicans familiar with Matheson out of the district and replace them with Republicans unfamiliar with him. That probably hurt him more than anything else. Over time, he overcame this problem.

It’s difficult to study intent, but it’s easier to study effects. I can’t say for sure what the legislature’s intent was back in 2001. But I can say that it’s not clear that the legislature actually made Matheson’s district more Republican in 2001.

This is part of a series of posts about redistricting in Utah. For an overview, read the introductory post. My talented research assistant, Robert Richards, contributed heavily to this series.

Possibly related posts:

• Redistricting backgrounders – What have we learned?
• Redistricting is not expected to change the partisan balance of Congress
• Redistricting backgrounders

Possibly related posts (automatically generated)

• Redistricting backgrounders – What have we learned? (June 13, 2011)
• Redistricting is not expected to change the partisan balance of Congress (September 28, 2012)
• Redistricting backgrounders (May 26, 2011)