When it comes to state elections, the shift in 2018 will probably be far smaller than the one in 2010

TO CHILL the spine of any Democratic politico, simply mention 2010. Most of them remember the catastrophic losses in the House of Representatives in the year of the Tea Party. Democrats lost 63 seats, their majority and their chance to enact meaningful policy after just two of Barack Obama’s eight years in office.

Many forget the carnage in the states, where Democrats lost 568 seats in state Houses, 136 seats in state Senates and six governorships (see chart 1). Before the 2010 elections, Republican “trifectas”—control over the governorship and both chambers of the state legislature—were present in just nine states. Afterwards the party had complete control in 21 states. Republicans now have trifectas in 25 states.

As a result, Democrats were shut out of the redistricting process in 2011, leading to gerrymandered boundaries that would reinforce Republican control for the next decade. To avoid another decade of wilderness-wandering, Democrats need to do well in state elections in a month’s time. Nearly 800 of the state legislators who will decide on redistricting after the 2020 census will be elected on November 6th. Thirty-six states will also choose a governor. Democrats are spending considerable energy on humble state elections. Several new progressive groups focused on state elections have sprung up since 2016. Rita Bosworth left her job after 12 years as a public defender to found Sister District, which helps activists in safe Democratic districts to volunteer in battleground ones. Catherine Vaughan, a former consultant at McKinsey, co-founded Flippable, which channels cash and volunteers to state races that are, well, flippable. Heather Stewart, a former television writer, led the New York division of Indivisible to topple six Democratic state senators who had caucused with Republicans, in effect granting them control of the chamber. This enthusiasm has already brought results. “The last Sunday before my election in November, it was a rainy, drizzly, dreary day,” recalls Kathy Tran, a Democrat elected to the Virginia House of Delegates in 2017. “We had a parking lot that was overflowing with volunteers—we knocked over 10,000 doors in one shift at 9am,” she says. Democratic gains in Virginia elections last year (the House remained in Republican hands only because a tied race was decided by drawing of lots) are looked to hopefully. Since November 2016 Democrats have flipped 44 state seats, whereas Republicans have flipped only seven. “Right now, Democrats control 32 state legislative chambers. By the end, we could have between 40 and 42 chambers,” says Jessica Post, the executive director of the Democratic Legislative Campaign Committee, which is more than doubling its spending on state contests. That sounds too optimistic. Chaz Nuttycombe, an independent handicapper, reckons that Democrats are on track to flip five chambers. To sense-check the forecasts, The Economist built a statistical model for state legislative control, then looked at the relation between the generic congressional polls and state elections. Despite its simplicity, the method explains 90% of the variation in election results. Applying it to current polls suggests that Democrats will pick up a modest 173 legislative seats. By comparison, the Republican wave in 2010 was three times that size. The state Senates in Colorado, Connecticut, Maine and New York are the most likely to change hands.