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The Republicans’ ‘Excess Seat’ Edge in State Legislatures

Dear Readers: In the latest edition of our Politics is Everything podcast, we talk with the author of today’s Crystal Ball piece — Senior Columnist Louis Jacobson — about his article today on “excess seats” in state legislatures as well as his journalism career with PolitiFact, House Republicans’ recently-announced impeachment inquiry into President Biden, and much more. Listen and subscribe here or wherever you get your podcasts.

The Editors


— We analyzed 48 states to see which have the most lopsided state Senate and state House chambers compared to how the state voted for president.

— Both parties have some states in which the legislative breakdown significantly exaggerates the patterns of the presidential vote.

— For Democrats, Hawaii, Rhode Island and Massachusetts have the most “excess seats” above the presidential vote threshold. For Republicans, the list is both longer and more varied, with Florida, Ohio, and Wisconsin standing out as at least somewhat competitive states where the Republicans have large excess seat advantages.

— In all, Republicans have proven much more adept than Democrats at leveraging presidential vote patterns into even larger majorities in state legislative chambers. The GOP has achieved significant levels of excess seats in about three times as many states as the Democrats have.

— Gerrymandering is one reason for this, but it probably doesn’t explain the exaggerated legislative majorities in many states. Rather, the phenomenon of excess seats appears to be a natural consequence of minority parties being doomed into irrelevance once they start consistently losing presidential and statewide races, sapping their ability to recruit candidates and build party infrastructure.

Excess seats in state legislatures

Recently, the Crystal Ball looked at the states that have “excess” U.S. House seats beyond what would be expected based on their 2020 presidential voting. In that analysis, we found a modest but growing edge for Republicans — that is, the GOP holds more seats in the House than the state-by-state presidential vote would suggest on its own.

Here, we’ll apply the same methodology to see which states have lopsided state Senate and House chambers, compared to what their presidential voting patterns would predict.

We began by calculating the share of the two-party presidential vote in 2020 for each party. Then we calculated the share of state Senate and state House seats for each party as of Aug. 24, courtesy of the National Conference of State Legislatures. (We ignored seats that were vacant at the time, as well as third party seats. We also ignored Nebraska, where the unicameral legislature is officially nonpartisan, and Alaska, where cross-party leadership alliances make party affiliation a less-than-useful indicator.)

Then, we took the two-party percentage of seats in each chamber for each party and subtracted from that the party’s share of the state’s two-party presidential vote in 2020. This left an “excess” percentage for each chamber. The higher that “excess” percentage, the more legislative seats the party has managed to squeeze out of a state.

In general, we found that Republicans have managed to squeeze more seats out of Republican-leaning states than Democrats have in Democratic-leaning states.

Which states are the most lopsided in the legislatures when compared to their presidential vote?

Either party can tout certain states in which their legislative numbers far exceed their share of the presidential vote.

For instance, in Hawaii and Rhode Island, the Democratic share of each legislative chamber is between 23 and 27 percentage points higher than Joe Biden’s share of the vote. In Hawaii, the Democrats currently hold 88% of seats in the House and 92% of seats in the Senate, both of which are well above Biden’s (still impressive) 65% of the vote in 2020. In Rhode Island, Democrats hold 86% of the Senate seats and 88% of the House seats, both of which exceed the 61% Biden won there.

The other state where Democrats hold an advantage of at least 23 percentage points in one chamber is Massachusetts. In the state Senate, Democrats hold 92% of the seats, compared with Biden’s 67% of the two-party vote.

For its part, the GOP has met this 23-percentage-point threshold for excess seats in both chambers in South Dakota, as well as in one chamber each in Ohio and North Dakota.

In South Dakota, the GOP holds 89% of the Senate seats and 90% of the House seats, compared to Donald Trump’s 63% of the two-party vote.

In Ohio, Republicans hold 79% of the Senate seats, compared to Trump’s 54% of the vote, and in North Dakota, the GOP holds 91% of the Senate seats, compared to Trump’s 67%.

Let’s turn to how strong the GOP edge is.

After removing Alaska and Nebraska, we broke down the remaining 96 chambers into five categories. For each type of chamber (Senate or House), we grouped together the states in which one party had achieved a double-digit margin in excess seats, the states in which one party had notched a 5 to 9 percentage point edge in excess seats, and the states in which the excess amounted to less than 5 percentage points for either party.

Here’s a chamber-by-chamber breakdown, ranked from most Democratic at the top to most Republican at the bottom. The figure listed is in percentage points — specifically the party’s percentage in the legislative chamber minus Biden or Trump’s percentage in 2020. This is also shown in Map 1 (for state Senates) and Map 2 (for state Houses), with positive numbers indicating Democratic excess seats and negative ones showing Republican excess seats.

State Senates

Map 1: Excess seats in state Senates

Democrats exceed their presidential baseline by at least 10 percentage points (7 states)

Hawaii, 27.0; Rhode Island, 25.9; Massachusetts, 25.2; California, 15.1; Delaware, 11.8; Nevada, 10.7; New Mexico, 10.3

Democrats exceed their presidential baseline by between 5 and 9 percentage points (6 states)

Illinois, 9.1; Colorado, 8.8; Maine, 8.2; Vermont, 7.6; Connecticut, 6.5; Maryland, 5.3

Division is within 5 points of presidential performance (8 states)

New York, 4.9 (Democratic edge); New Jersey, 4.4 (Democratic edge); Michigan, 1.2 (Democratic edge); Oregon, 0.3 (Democratic edge); Virginia, 0.2 (Republican edge); Washington, 0.7 (Republican edge); Minnesota, 2.9 (Republican edge); Arizona, 3.5 (Republican edge)

Republicans exceed their presidential baseline by between 5 and 9 percentage points (6 states)

Pennsylvania, 6.6; Texas, 8.5; Georgia, 9.0; North Carolina, 9.3; Montana, 9.6; Louisiana, 9.8

Republicans exceed their presidential baseline by at least 10 percentage points (21 states)

Mississippi, 10.8; New Hampshire, 12.1; South Carolina, 12.3; Missouri, 12.8; Iowa, 13.8; Idaho, 14.1; Alabama, 14.2; Kansas, 14.3; Oklahoma, 16.4; Wisconsin, 17.0; Florida, 18.3; Kentucky, 18.4; Utah, 18.6; Arkansas, 18.7; Tennessee, 20.0; Wyoming, 21.1; West Virginia, 21.4; Indiana, 21.8; North Dakota, 24.3; Ohio, 24.7; South Dakota, 25.1

State Houses

Map 2: Excess seats in state Houses

Democrats exceed their presidential baseline by at least 10 percentage points (6 states)

Rhode Island, 27.2; Hawaii, 23.2; Massachusetts, 17.2; Nevada, 15.4; Colorado, 13.8; California, 12.6

Democrats exceed their presidential baseline by between 5 and 9 percentage points (5 states)

New Mexico, 8.3; Illinois, 7.4; New York, 6.1; Vermont, 5.5; Maryland, 5.3

Division is within 5 points of presidential performance (12 states)

Connecticut, 4.7 (Democratic edge); Delaware, 3.8 (Democratic edge); Oregon, 0.03 (Democratic edge); Michigan, 0.5 (Republican edge); New Jersey, 0.6 (Republican edge); Pennsylvania, 0.6 (Republican edge); Maine, 0.6 (Republican edge); Washington, 0.7 (Republican edge); Minnesota, 1.4 (Republican edge); Arizona, 1.8 (Republican edge); New Hampshire, 4.0 (Republican edge); Texas, 4.5 (Republican edge)

Republicans exceed their presidential baseline by between 5 and 9 percentage points (7 states)

Georgia, 6.8; Virginia, 7.2; Mississippi, 7.4; Louisiana, 8.8; North Carolina, 9.3; Montana, 9.6; Iowa, 9.8

Republicans exceed their presidential baseline by at least 10 percentage points (18 states)

Kansas, 10.5; Missouri, 10.7; Alabama, 10.9; Indiana, 11.8; Oklahoma, 13.3; Ohio, 13.6; Tennessee, 13.9; Wisconsin, 15.0; South Carolina, 15.0; Kentucky, 17.6; Arkansas, 17.8; Idaho, 18.4; Florida, 18.6; West Virginia, 19.2; Wyoming, 19.5; North Dakota, 20.0; Utah, 20.6; South Dakota, 26.6

The first thing that jumps out from these results is that, from a national perspective, the Republicans have been far more successful at winning excess legislative seats than Democrats have.

In 7 Senate chambers and 6 House chambers, the Democrats have exceeded their share of the presidential vote by at least double-digit percentages. But the Republicans have done so in 21 Senate chambers and 18 House chambers — exactly three times the number of states where Democrats have done it.

So, while unusually large Democratic legislative majorities in a few states might be tempted to outrun their voters’ tolerance for progressive policies, the Republicans could pursue more conservative policies than the presidential vote would suggest in three times as many states.

It’s no surprise, then, that the list above is chock-full of states that have passed the most stringent abortion laws in the country. And in three of these states — Kansas, Kentucky, and Ohio — voters have rebelled by backing ballot measures aligned against further curbs on abortion access. This suggests that the GOP’s excess legislative majorities might be underestimating their constituents’ desire for more moderate policies.

While these lists indicate that the winner of the presidential vote and the legislative majority in a given state tends to be highly correlated, there are some notable exceptions — and they only accrue to the GOP’s benefit.

Currently, the GOP controls both chambers in four Biden-won states: Arizona and New Hampshire narrowly, and Georgia and Wisconsin by wider margins. The GOP also controls one chamber each in two other Biden-won states: Pennsylvania’s Senate and Virginia’s House.

The Democrats, by contrast, don’t control a single legislative chamber in a state won by Trump.

To be fair, with the exception of Virginia, the 2020 presidential margins in these states were relatively close, so having a split between legislative control and presidential vote is not too surprising.

But one state does deserve special mention: Wisconsin. It is there that Democrats have long complained about gerrymanders that left Republicans with commanding legislative majorities despite a repeated history of close races in federal and statewide contests. With a Democratic-aligned justice recently ascending to the state Supreme Court with a double-digit victory, effectively tilting the court’s balance towards the Democrats, the party hoped it would be an opportunity to create new legislative maps that are more balanced. But now, Republican legislators are taking a serious look at impeaching the justice before she’s even ruled on a case, something made possible (if not necessarily popular) by their excess-seat advantages in the legislature. The GOP has also floated trying to implement a new redistricting system modeled off of the one in Iowa, where nonpartisan experts draw a map that then faces an up or down vote in the legislature. But Democrats see this as a proposal designed simply to preempt action by the state Supreme Court.

Why do these states have excess seats for one party?

The most obvious reason for excess seats — but not the only one — is gerrymandering.

This probably does explain much of the disparity in Wisconsin, and a number of other states with the largest excess-seat advantage for Republicans have also been known for aggressive gerrymanders in the post-2020 census period, including Tennessee and Florida. It may be a factor in other states too, such as Ohio and Utah. (Democrats can also gerrymander when they have the opportunity to: Nevada stands out as a politically balanced state where Democrats drew the maps and have an excess seat edge in both chambers.)

However, not all lopsided legislatures have been created by gerrymandering. Sometimes the political geography of a state makes it hard to draw enough districts for the minority party to match their share of the presidential vote. This is often said about Massachusetts, for instance, or also for Wisconsin.

There can also be an intersection of geography and gerrymandering that contributes to the Republican excess seat edge, in which Democratic-leaning constituencies can sometimes be clustered together in certain places, leading to challenges in converting the number of votes cast into the number of seats won.

My guess, though, is that gerrymandering, and even geography, matters less than one might think. I suspect that it has more to do with the minority party turning headlong into a spiral of irrelevance.

Particularly given the recent decline of voter willingness to split tickets, there comes a point at which a party’s weakness in presidential, congressional, and gubernatorial contests becomes a self-fulfilling prophecy. Once a party’s prospects seem grim in a particular state, it becomes hard to get credible candidates to run for office, and it becomes hard to raise money to fund a decent party infrastructure.

And the fewer talented and adequately funded candidates mustered by the minority party, the more potentially winnable seats that minority party has to concede to the powerful, well-funded majority party. A minority party may be so weak that it can barely keep its own incumbents in office, much less contest seats held by the majority party. At some point, this pattern reinforces itself, as credible candidates begin to join the only party with a realistic chance of making things happen in the legislature: the majority.

In the states with the biggest shares of excess seats, this phenomenon has been under way for years. It has occurred in blue states like Hawaii, Rhode Island, and Massachusetts, and in red states like the Dakotas, Wyoming, and Idaho. In both cases, the minority party has become so weak that it cycles into irrelevance.

A state’s size may be a factor as well. The states with the heaviest loads of excess seats tend to be small, or at least smallish. While California for the Democrats and Florida for the Republicans do belong in the category with the most excess seats, most of the bigger states by population cluster around the middle of our rankings. This may be because it’s even harder to keep a minority party afloat in a lightly populated state where a determined majority can more easily control the levers of power in the legislature.

In many of these states, in fact, the majority party has become so dominant that it’s turned into a broad tent riven by ideological factions. In states like Rhode Island and Idaho, the divisions that matter are within the majority, not between the two parties. (In Rhode Island, the Democratic Party is split between progressives and moderates, while in Idaho, the GOP has been divided between conservatives and the far right.)

Whatever the reason for these in-state dynamics, the Republicans seem to be better at leveraging extra seats in a wider swath of states. So while both parties risk creating legislative majorities that are ideologically more extreme than their voters, the GOP has to worry about this in more places. Unless, that is, voters ever decide that it’s preferable to empower their state’s withered minority party instead.

Louis Jacobson is a Senior Columnist for Sabato’s Crystal Ball. He is also the senior correspondent at the fact-checking website PolitiFact and is senior author of the newly released Almanac of American Politics 2024. He was senior author of the Almanac’s 2016, 2018, 2020, and 2022 editions and a contributing writer for the 2000 and 2004 editions.