7,383--that's how many state legislative seats there are in the country. Right now, the Republicans control around 1,000 more seats than the Democrats with unified legislative control in around two-thirds of states.
6,066 of these seats are up in the 2018 election. Joan Walsh does an excellent job of running down this situation--and opportunities/challenges for Democrats--in her mammoth recent article in the Nation.
As I've noted before, do not sleep on these elections. In some ways, they could be more important than the race for the House. After all, even with very favorable results in the House (and the Senate), 2018 is not likely to be the start of a new progressive era in the United States. No, that is really a 2020's thing when President Trump is (hopefully) defeated and Democrats have enough strength in the states to dominate the next round of redistricting, thereby allowing them to push back against Republican gerrymandering and translate their underlying political support into actual political victories.
That's where the 7,383 (or 6,066) seat strategy comes in....