Gerrymandering Isn’t Giving Republicans the Advantage You Might Expect

There is no shortage of reasons why Republicans are expected to retake the House this year, including President Biden’s low approval ratings and a long history of struggles for the president’s party in the midterm elections.

But there is another issue looming over the House race, one that has nothing to do with the candidates or the voters: the fairness of the newly redrawn congressional maps.

It could be assumed that the House map is heavily rigged toward Republicans, especially after Republicans enacted aggressive rigs in critical states like Texas and Florida. Many of you might even assume that this gerrymandering means that the House will not only lean Republican, but is also out of reach for Democrats under realistic circumstances.

In reality, the Republicans have a structural advantage in the House, but it is nothing insurmountable for the Democrats. By some measures, this is the most beautiful house map of the last 40 years.

Here’s one way to think about it: If you think Democrats have a good chance of winning the Senate, they should at least have a chance of winning the House, even if Republicans are favored there.

Let’s start with a simple fact: On the new House map, 226 districts would have voted for Biden in 2020, compared to 209 for Donald J. Trump.

Now, Mr. Biden has won the national vote by 4.5 percentage points, so even a map that is skewed toward Republicans could have more Biden districts than Trump districts. But the simple fact that Biden carried most districts is a pretty clear indication that the Republican advantage in the House is not entirely insurmountable.

To account for Biden’s victory in 2020, a somewhat better, if more complex, measure is needed: a comparison between how districts voted and how the nation as a whole voted. If Mr. Biden won a district by more than he did nationally, it’s arguably a district where Democrats have the upper hand if the national vote is tied. On a perfectly fair map, half of the districts would lean Democratic relative to the nation, while the other half would either vote for Trump or vote for Biden by less than 4.5 points. And on this perfectly fair map, the district right in the middle, the Central District, would have voted for Mr. Biden by 4.5 points, as would the nation.

So how does this House see itself with those measures? The median district backed Biden by 2.1 points, slightly more to the right than the nation as a whole. And overall, there are 215 districts where Biden has won by at least 4.5 percentage points, compared to 220 districts where Trump has won or where Biden has won by less than 4.5 points.

Both measures show a map tilted toward the Republicans. To retain control of the House in our hypothesis, Democrats would have to win at least three districts where Mr. Biden fared worse than the entire country, including one district where he won by 2.1 points or less. In theory, Republicans could prevail by defending districts where Trump won or lost less than the entire country.

This is a true Republican advantage, but not an intimidating one for Democrats. Here are three ways to put it into perspective.

First, the Republican advantage is flimsy. In a chamber with dozens of competitive races, a three-seat lead isn’t much. If Republicans nominate too many ineligible candidates to stop the theft or if too many Democratic incumbents prove too resilient, the Republican structural advantage would evaporate.

Second, the edge is historically small. In fact, there are more Democratic-leaning districts (215) than at any time in the last 40 years.

As recently as 2012, there were only 195 districts in which Barack Obama had done better than average across the country in previous elections. That was such a big advantage that you could really (and I did!) rule out the possibility of a Democratic win any time soon, even if the party could narrowly win the House popular vote. Not anymore.

Third, the Republican structural advantage is quite comparable to that of the Senate and the Electoral College — two bodies where, yes, the Republicans have structural advantages, but where no one really questions whether the Democrats they can victory.

Consider this: While the Democrats could win the House by winning every district Biden carried by at least 2.1 points, the Democrats would lose the presidency and the Senate if they only won the states where Biden carried by 2.1 or more. In the Senate races, seats in Georgia and Arizona would switch to Republicans, while Democrats would fail to switch seats in Pennsylvania, Wisconsin, North Carolina and Ohio.

Or put another way, if Democrats can win House races that resemble Senate races in Arizona, Georgia, Pennsylvania and Nevada, they can probably win the House.

There is a catch to this comparison, and this is where the gerrymandering comes in: Democrats will need to win a higher proportion of competitive districts than they do in the Senate.

For illustration, let’s define a “competitive” state or district using what we’ll call the North Carolina-Virginia range, which means identifying each district that voted between Mr. Trump’s 1.3-point victory in North Carolina and Mr. Biden’s 10.1-point victory. in virginia This is a convenient measure because both states diverged about 5.7 points of the national vote in 2020, North Carolina to the right and Virginia to the left.

To win the Senate this year in our scenario, Democrats would need to win four of the seven races in the range from Virginia to North Carolina. To win the House, Democrats would need to win about 72 percent of the districts in that area from Virginia to North Carolina, or five in seven races.

Winning five of seven competitive seats is a difficult burden for Democrats, especially in a midterm year. But it’s impossible? Certainly, it’s not impossible that Democrats will win five of the seven key Senate races; in fact, Democrats may well be favorites in five of the seven Senate races right now. An equally impressive House race might be more of a challenge, but Democrats would bring many of the same advantages to the table, like steal-proof Republican nominees and a disproportionate number of Democratic incumbents.

None of this means that the Democrats will win the House. But if they don’t, it may not be that simple to blame gerrymandering.