From left, former Alaska governor Sarah Palin, Sen. Ted Cruz (R-Tex.), Sharon Lee, Sen. Mike Lee (R-Utah) and former Nebraska governor Kay Orr on April 25 in North Platte, Neb., at a rally for Republican U.S. Senate candidate Ben Sasse. (Job Vigil/The Telegraph via Associated Press)

Watching the Nebraska Senate primary results tonight?

As usual, The Fix likes to give you a scorecard to keep track. Here's a quick rundown of who needs to win and where in the GOP primary between Ben Sasse, Sid Dinsdale and Shane Osborn. It's our list of five key counties:

Douglas County:  This is the state's most-populous county (including Omaha) with more than one-fourth of the state's population and about one-fifth of GOP primary voters. Dinsdale, a banker from Omaha, will probably want to win this area by a decent margin in order to have a good shot to win -- both because it's his home and because it's the state's least-conservative area. Dinsdale, as the Wall Street Journal's Reid J. Epstein notes, has run more on his Nebraska roots than his ideological purity, which isn't exactly his strong suit.

It's also worth noting that Osborn lives in Douglas County -- though given his experience in statewide office, he's less reliant on a certain region. Sasse is from nearby Dodge County, so he's got some Omaha-area roots too.

Lancaster County: The second most-populous county in the state, this one is home to Lincoln. It was also a big source of votes for Osborn when he won his 2006 primary for treasurer. While he took 63 percent statewide, he took 68 percent in this county. Osborn was no slouch in Douglas, though, taking 66 percent there. He performed less well in rural counties, but still won all over the state.

Hall County: They say the 3rd Congressional District decides statewide GOP primaries -- and that goes double when all the candidates are from the Omaha area in far eastern Nebraska. The highly rural 3rd generally comprises about 40 percent of GOP primary voters, despite being one-third of the state's population. It's also very conservative and older. Sasse needs to win counties like this one, which is the biggest in the 3rd district and home to Grand Island. And he probably needs to do it by a good clip.

Buffalo County: This county neighbors Hall and is home to Kearney. Pretty much all of the Buffalo County stuff also applies here. The two counties comprise between 5 and 6 percent of the primary electorate, so they are more bellwethers for western Nebraska than big sources of votes.

Dodge County: This county is home to Midland University, where Sasse serves as president. It's also quite close to Omaha, though, meaning it's not clear that Sasse has a big advantage. In fact, you could make an argument that each man has a pretty good shot here -- Osborn's 2006 numbers were close to his statewide numbers -- so it might be an indication of where the broader race is headed.