It's difficult say succinctly just how difficult Democrats' path back to power is. They are still winning the popular vote for president, after all, and they seem to have both the House and the Senate majorities within grasp if the cards fall right! How bad could it really be?

But Democrats' ability to regain power on a sustained basis is a much tougher proposition. It will basically require one or both of two things: 1) a realignment that shifts the U.S. political center to the left, and/or 2) somehow clawing back from their historically bad position in state legislatures.

The first of those is largely out of their control; the second is immensely difficult. That's because Democrats are in the midst of a vicious cycle at the state legislative level. They are at historic lows in terms of the percentage of seats and chambers they hold, and that same powerlessness is preventing them from drawing the maps they need to have a fighting chance over the long term.

Republicans used big gains in the 2010 election to draw friendly maps across the country, and those very same maps are making it extremely difficult for Democrats to be able to draw the new ones after the 2020 election — not to mention congressional maps. Democrats' best hope in many swing states is to win the governor's mansion, where they could at least have veto power over the maps drawn by GOP-controlled legislatures. Without that, they may be in for 10 more years in the political wilderness.

But just how tough a spot are Democrats in in those legislatures?

Daily Kos Elections's Jeff Singer has been crunching the numbers and found something rather remarkable: In 77.5 percent of state legislative chambers for which it has data, the median district — the one in the middle of all the districts, according to partisanship — was redder than the entire state. That's 62 out of 80 chambers across 40 states.

Why that's important: These are the kinds of districts Democrats will absolutely need to win if they are to win majorities, and in the vast majority of states they need to do even better than you might think based on the statewide vote — sometimes by a lot.

In Michigan, for example, Trump won the state by just 0.2 percent, but the median state Senate district voted for him by more than 10 points, and the median state House district went for him by 9.2 points.

In Wisconsin, Trump won by less than a point, but the median state Senate district went for Trump by 10.6 points, and the median state House district went for him by 9.9 points.

North Carolina is one of the most extreme examples. Trump carried the state by four points, but the median state House district went for him by 11.9 points, and the median state Senate district went for him by 17.9 points!

The two maps below show how the median state legislative districts in each of the 40 states compare to the statewide presidential vote, first for state Senate districts and then for state House districts. The redder the state, the more Trump-friendly the median district was than the state as a whole, and vice versa for the blue states.

One thing to keep in mind in both of these maps: Trump won 30 out of 50 states, so we're already starting with a map full of mostly red states. And the median state legislative districts, on average, are 3 to 4 points redder than that.

Democrats just don't benefit from the same kind of imbalances in key states. Only in Maryland is there even one chamber with such a big difference between the statewide vote and Democrats' advantage in the median district. Trump lost the state by 27 points, but he lost the median state Senate district by 35 points and the median state House district by more than 40.

This is because Maryland is one of the few populous states with Democrats in charge and able to draw a favorable map. Republicans had this power in nearly half the country, including the three states mentioned above.

Not all of these advantages are due to gerrymandering — some of it is simply that Republican voters are naturally more dispersed than Democratic ones — but that is a huge part of it. In gerrymandering, the more districts you have, the more creative you can get. While the parties can only do so much with the handful of congressional districts they get to draw, state legislative maps can be drawn to be something close to impenetrable for the other side.

And when Democrats need to be winning territory that Trump won by 10 points to even have a shot at a majority — and to draw important congressional maps — that shows you just what a tough spot they are in.

Kevin Uhrmacher contributed to this post.