Democrats have just won their two most important elections in a decade – and it has nothing to do with Donald Trump

There was plenty for Democrats to get excited about during the state and governor elections in Virginia and Kentucky on Tuesday – but the biggest cause for cheer may not be what you think.

The Democrat wins have already been interpreted as a major blow for Donald Trump, and they are, in general. It is never a good look for a Republican to lose a governorship in a state as red as Kentucky, even if Matt Bevin is refusing to concede a close result. The fact that the president was there on Monday talking up Bevin’s chances only makes things worse.

But Bevin is not a popular governor, hence why Democrats thought they had a sniff at an upset. The major result was actually the Democrats taking control of the Virginia state legislature for the first time in more than two decades, and it could prove to be more important than any result the party will have in the next 10 years – and that includes the White House in 2020.

State legislatures are as polarised as any other part of American politics, with either Democrats or Republicans having a majority in every state bar one, Minnesota. With a census taking place next year, control of these legislatures is all important. The winning party will be the one getting to redraw electoral maps.

These affect state-level elections, but also those on a national level. Republicans were very quick to cotton onto this after the midterm elections of 2010 and the census that year. In a number of cases that has led to a redrawing of maps, solidifying GOP control of some states. While some were knocked down by the courts on racial discrimination grounds, a recent Supreme Court decision to refuse to hear two partisan gerrymandering cases – from Maryland and North Carolina – means that there will likely be no federal block on the practice.

The nation’s top court left open the door to state courts to take decisions on electoral maps, and a North Carolina court has ruled the maps there – where Republicans have a 10-3 advantage when it comes to seats in congress – must be redrawn. The state has a significant number of Democrat voters – 46 per cent voted for Hillary Clinton in 2016 – and the court has decided they are not being represented fairly.

State legislatures are important. If Democrats have them they can pass legislation to give some former felons the vote and other measures. Some states also have the ability to help select state-level judges which, given the conservative majority on the Supreme Court, will have an important part to play in defending issues like abortion access that most Democrats want to protect.

Then there is redrawing the congressional districts. Particularly in the Senate, where significant change in the make-up of the chamber can take many election cycles, redrawing fairer maps will make a difference.

The Democrats now realise their error of 10 years ago and are making a big push to flip legislatures. They have been joined by a number of rights groups and single-issue campaigns, such as Emily’s List, who have pledged vast sums knowing what is at stake.

Virginia was the first step in this plan. It has long been marked as the most winnable of all the states given how close the seats were. But it cannot be overestimated how much difference a winning start can make.

More groups will be encouraged to spend, and it gives Democrats momentum going into 2020. More top-tier politicians will be minded to stump for local candidates and the general effort.

A mobilisation against Trump has obviously helped when it comes getting activists out on the street – but this goes beyond the presidential campaign in 2020.

This is about 2022, the presidential election in 2024 and beyond. If the trend continues, the Democrats may have just helped ensure their agenda has a chance of shaping the nation into the 2030s.