Election night is long — sometimes very long. Sometimes it lingers for weeks or even months. And even longtime analysts like yours truly have a difficult time processing the results of 435 House races and 33 to 35 Senate races, in real time, to figure out what it all means.

One method I’ve always found helpful is to zero in on a few key races — ones that are early in the night, representative of the broader electoral battle, and/or might signal a wave for either party (in this case, the Democrats).

Here are some of those races.

Indiana Senate

As one of the two states where most polls close at 6 p.m. Eastern time (along with Kentucky), Indiana often provides early insights. And this year, there is a very close Senate race that could indicate which way control of that chamber might tilt.

Sen. Joe Donnelly (D) faces Republican Mike Braun in a race that has been competitive from Day One; the most recent RealClearPolitics average has Donnelly up less than a point. It also happens to be one of several very red states that Democrats were forced to defend on a tough 2018 Senate map.

If Republicans knock off Donnelly at the start of the night, it would be a huge, possible fatal blow to Democrats' majority math — and suggest other such red states could fall as the night progresses, like Missouri and Montana. Given Democrats' need to win at least one of either North Dakota, Texas or Tennessee to get the majority, and given that all of those states are tougher than Indiana, we’d probably be talking about a status quo Republican majority, if not GOP gains. Losing Indiana would mean Democrats would need to win at least two of those for the majority, which is a very tall task.

On the other hand, if Donnelly wins and even exceeds expectations in a state President Trump won by 19 points, we would have to at least leave the door open for a Senate takeover.

Florida Senate

It’s always about Florida, and this year is no exception. Most polls close there at 7 p.m. Eastern time and the rest at 8 p.m., and while this race is obviously key to control of the Senate — Democrats almost definitely need it — it could also provide some broader clues about the election.

Polling here has jumped around quite a bit, with Sen. Bill Nelson (D) starting off ahead, Gov. Rick Scott (R) seizing a lead for a while, and then Nelson reclaiming it. Nelson is up by three points right now in the RCP average.

This is the only early Senate race happening in a swing state. If Democrats can’t hold a state like this, their majority math is virtually nonexistent in the Senate, and it may start to look a little dicier in the House as well. Frankly, you’d expect Democrats to hold a state like this in a good year with a longtime incumbent on the ballot, even if his opponent is a sitting governor.

Kentucky’s 6th District

This race embodies Democrats' high hopes for peeling off conservative-leaning districts thanks to strong candidates, and the suburbs turning against President Trump. Its polls also close at 6 p.m., making it the first big one where constituents are done voting.

Rep. Garland “Andy” Barr (R-Ky.) has taken at least 60 percent the last two elections, and the district was carried by Trump by 14 points and Mitt Romney by 16. But Democrats have a top-tier recruit in former Marine fighter pilot Amy McGrath, who raised a stunning $3.65 million in the third quarter of fundraising — a total usually associated with Senate candidates. It’s close — so close that Donald Trump Jr. made a late appearance.

If McGrath wins, Democrats will feel like the night is progressing as they hoped, and that the majority is very possible. A Barr win wouldn’t negate that possibility, but it would suggest the path becomes tougher, and maybe it’s not a huge wave.

Georgia’s 6th District

If the above district sounds familiar, it’s because it hosted the most expensive House race in history in a special election last year. Democrat Jon Ossoff came up just short, but Democrats have put it in play again.

Even more so than Kentucky’s 6th, it’s one of those districts where the suburbs tell the tale and could buck Trump. In fact, between the 2012 and 2016 presidential races, it turned more against Trump than all but five other districts. Romney won it by 23 points, but Trump eked it out by 1.5 points.

Democrats' 2017 loss here was a heartbreaker for exactly that reason: They thought the environment and anti-Trump fervor in such districts meant they could win in previously unthinkable territory. If Democrat Lucy McBath unseats Rep. Karen Handel (R) on Tuesday, after all that disappointment, Democrats will have both the signature win that previously eluded them and a very good sign that a wave is coming.

The polls here close at 7 p.m. Eastern time.

Virginia’s 7th District

Speaking of districts that were previously unthinkable Democratic targets: the old one of former House majority leader Eric Cantor (R-Va.) is suddenly a toss-up. Cantor’s 2014 primary usurper, Rep. Dave Brat (R-Va.), is in a close race with Democrat Abigail Spanberger. This is another district that has trended away from the GOP and seemed to be pretty anti-Trump — in part because a new court-drawn map added parts of Democratic Richmond.

A Democratic win here would suggest a possible House takeover, at the least. It’s probably more of a race Democrats should win than the ones above, but wins in any of the three would be good news for them. Winning two of the three would be very good news.

The governors

Perhaps the most undersold races of 2018 are a handful of governors' races. Why? Because Republicans hold a historic amount of control over state legislatures, and without Democratic wins in these key governors' races, the GOP could again draw big and important congressional maps after the 2020 Census — just like they did after 2010. Those GOP-friendly maps are a big reason Democrats aren’t guaranteed a House takeover Tuesday night.

I’ve keyed in on six states with GOP state legislatures, malleable maps with lots of congressional districts, and a contested governor’s race this year. They are:

  • Florida
  • Georgia
  • Michigan
  • Ohio
  • Pennsylvania
  • Wisconsin

Democrats are favored to win in Michigan and Pennsylvania, which would be big for them. The biggest early prize of the night — and the biggest prize overall — is Florida, which has 29 congressional districts and a tight race between Rep. Ron DeSantis (R) and Tallahassee Mayor Andrew Gillum (D).

Neighboring Georgia, which is between Democrat Stacey Abrams and Republican Brian Kemp, may not be decided Tuesday night, given there’s a runoff if no candidate gets 50 percent. But Ohio (where polls close at 7:30 p.m. Eastern time) will also be a big early one with major, decade-long implications.