One way to illustrate how much the GOP-drawn state Senate map protects the Republican majority is to sort each seat in each chamber by Clinton's margin of victory over Trump and see how the seat in the middle—known as the median seat—voted. Because both chambers have an even number of seats, we average the two middle seats to come up with the median point in the chamber. Trump carried the median seat 52-42, about 10 points to the right of his very thin statewide win.
We’ll turn to the state House, which has been a bit more friendly to Team Blue but is still a tough lift. Democrats managed to flip the chamber in 2006 and held it in 2008, but the GOP took it back in the 2010 wave and they’ve kept it ever since. The median seat went for Trump 52-43, again well to the right of his narrow statewide win.
Unlike in the state House, ticket-splitting actually worked in the Democrats’ favor overall. In 2016, Democrats won eight Trump seats while the GOP took four Clinton seats. However, seven of those eight Democratic seats had backed Obama four years before, while three of the GOP-held Clinton seats went for Romney. Six additional Republicans hold Obama/Trump seats. The only Democrat in a Romney-Trump seat is Scott Dianda, whose HD-110, which is located on the Upper Peninsula, went from 52-47 Romney to 57-38 Trump. Dianda won re-election 61-39 last year, but he will be termed-out in 2018. The lone Republican in an Obama/Clinton seat is Brandt Iden, whose Kalamazoo County HD-61 went from 50-49 Obama to 49-45 Clinton. Last year, Iden won re-election 49-45, and he’s eligible to serve one more term.
Democrats have to defend one of their eight Trump seats in a special election this November, and both parties will hold primaries in August. The vacancy came about for very tragic reasons: Earlier this year, Democratic state Rep. John Kivela, who won re-election 62-34, died in an apparent suicide. His HD-109, which is located in the Upper Peninsula, swung from 53-45 Obama to 49-45 Trump.
As strong as the GOP’s gerrymanders are, they may not be completely impenetrable. During the 2014 GOP wave, Democrat Gary Peters defeated Terri Lynn Land, one of the feeblest Republican candidates anywhere (see this genuine Land ad for a taste), by a wide 55-41 margin. Peters carried 25 of 38 districts in the Senate and 74 of 110 in the House. And while both Obama and Clinton won the same four congressional districts, Peters narrowly carried four more districts, all won by both Romney and Trump: MI-04 (represented by Rep. John Moolenaar), MI-07 (Tim Walberg), MI-08 (Mike Bishop), and MI-11 (Dave Trott).
Peters’ decisive win didn’t mean much for Democrats downticket in 2014, though. Three Republican incumbents, Gov. Rick Snyder, Attorney General Bill Schuette, and Secretary of State Ruth Johnson, were all re-elected statewide, and the GOP expanded their majorities in both legislative chambers and held all their congressional seats. Still, if 2018 continues to shape up as a strong year for the entire Democratic ticket in Michigan, even the GOP’s seemingly rock-solid gerrymanders might not be enough to protect their majorities. And if Democrats can retake the governor’s office next year, they can veto any GOP attempt to draw another gerrymander for the next decade.