Gov. Scott Walker (R-Wis.) would be justified in feeling a little panicked.

On Tuesday night, voters in the 10th state senate district in Wisconsin unexpectedly chose Democrat Patty Schachtner over Republican Adam Jarchow. It’s a district that in 2016 backed Donald Trump by 17 points. Schachtner won by nine.

The election was a “wake up call” for Republicans in Wisconsin for the 2018 elections, Walker tweeted (then tweeting seven separate times reasons that the result should be an all-caps WAKE UP CALL). For Walker, this isn’t just about party loyalty: It’s about the fact that he is up for reelection in November, and swings of 20-plus points to the Democrats is not the sort of thing that an incumbent Republican likes to see.

It’s not the sort of thing that Republicans nationally want to see either. Not because they lost this particular race (though certainly they’re not excited about that). Instead, it’s part of a pattern that’s emerged since the 2016 election: Big shifts to the Democrats and a slew of pickups by the party in state races — and, in Alabama, federal.

DailyKos has been tracking special election results since December 2016, comparing the results of the contests with the results of the 2016 election in the same districts. The pattern has been consistent, if not uniform: Democrats have gained, on average, 14 points in their 2016 presidential margins against Republicans in special elections. This is only including special elections, mind you; it excludes the big swings in Virginia that drew the Democrats close to a majority in the lower chamber in that state.

In some blue states and Florida, that pattern hasn’t held. Republicans have seen gains relative to how Trump fared in 2016 in a number of seats. But broadly, the shift has been to the left — and big. (On the maps below, states are colored relative to their 2016 vote for president.)

A critical point — one that Republicans will often hasten to note — is that the Democrats have made a lot of gains but have picked up far fewer seats. That’s the story of the House races in 2017: Democrats often vastly overperformed Hillary Clinton’s effort in 2016, but still didn’t actually win seats. That’s also because a lot of the races where there have been special elections were in heavily Republican areas, where picking up 10 points doesn’t matter if the Republicans usually win by 15.

Walker won his reelection in 2014 by less than eight points.

Speaking of Clinton, this shift is not solely a function of her unpopularity as a candidate. After all, local Democrats without Clinton’s strong unpopularity might fare better in local matchups. But if we look at the shifts relative to the 2012 election, the pattern is still similar. In special election contests, Democrats gained an average of seven points relative to Barack Obama’s margins that year.

Part of the expected shift to the left in 2018 is that the Republicans did so well in state and federal elections in 2010 and 2014, picking up a lot of seats that the Democrats had won in 2006 and 2008. The Democrats lost a ton of seats during Obama’s presidency, but that’s in part a function of the Republicans picking off seats in places where Democrats had overperformed in wave elections. Republicans now have a similar problem in some places.

But part of the problem, too — a big part — is the deep unpopularity of President Trump. Some large percentage of the special election results since the presidential election can be attributed to Trump’s unpopularity and the desire of Democrats to express opposition to him. More Alabama voters told exit pollsters during the recent special Senate election that they wanted to show support for Trump than opposition to him — but this is Alabama, one of the reddest states in the country, and fully one-fifth of voters went to the polls in the state to explicitly express opposition to a Republican president.

That also can’t be reassuring to Walker, who’s generally a Trump ally. His state bucked its recent history to support the Republican in the 2016 presidential election, but that was then. In November, if the rest of the state sees a shift that’s even half as big as the one in the special state senate election on Tuesday, Walker will likely find himself out of a job in 2019.