In the past, midterm elections have been kind of predictable. The president is slightly unpopular, his party loses some seats and most voters disappear for two years until they turn up in greater numbers for the main show. It’s been a pretty consistent pattern; since 1934, the president’s party has lost in almost every single midterm election, gaining House seats just three times and Senate seats in only six of the 22 midterm votes.

This year might not buck any of those long-term trends. The Democratic president Joe Biden has watched his popularity slump from 53% to 42% over the past year. Polls suggest that Republicans will win the House of Representatives and might even win the Senate too (though if they do, it’s likely to be by a narrower margin). And even though turnout is looking set to be historically high by midterm standards, it’s unlikely to beat the numbers in 2020. So, it’s all pretty much electoral business as usual, right?

Not quite. Here are some of the factors that could shape the votes that come in over the next few days – and, as a result, shape the country over the next few years.

Under Trump, gerrymandering and other anti-democratic measures scaled up. There have been concerns about the way that kind of partisan redistricting might play out in this year’s elections – where the electoral district is purple, this is likely to work in Republicans’ favor including parts of Texas and Florida.