For the moment, Joe Biden is leading Bernie Sanders in the earned delegate race by 96, and some observers are predicting that Uncle Joe will score some big wins tonight. (We need to specify “for the moment” because votes are still being counted in California, Texas and several other Super Tuesday states.) In tonight’s Not So Super Tuesday races there are 352 earned delegates available. If any of the recent polling can be trusted – a big “if” these days – several of these races appear to be very close. But as the Associated Press explains in an analysis this week, that’s going to be particularly good news for whoever comes out on top in the states where the margins are tight. The “quirk” in the system comes from the way the delegates are allocated. (The Hill)

The intricate arithmetic of how delegates are won under Democrats’ rules makes it possible for a candidate to reap a bigger haul of delegates with a smaller margin of victory on this Tuesday than on any other night.

For Bernie Sanders, it’s an opportunity to catch up to Joe Biden, who enters the day ahead by 96 delegates. For Biden, it’s a chance to open up what could become an insurmountable lead.

How this happens may seem complicated, but it’s nothing more than some basic math and an “odd” quirk of how delegates are won under party rules.

Here’s how this “quirk” shakes out. Each state is broken down into congressional districts, each having some delegates to award. There are two additional groups of delegates representing the Senators. The congressional district delegates are awarded proportionally to anyone getting more than 15% support in each district while the senate delegates are proportionally awarded based on the statewide results.

In every district and state where the two candidates are close (with the “winner” getting less than roughly 58% support), they split the delegates evenly. But some districts have an odd number of delegates, so even if the winner only gets 51%, they wind up getting the extra, “odd” delegate. As the AP points out, tonight’s races contain the largest number of districts and states with an odd number of delegates. Roughly two-thirds of the 352 available this evening fall into that category, while the rest of the states yet to vote have a vastly larger proportion with even numbers of delegates.

The bottom line of all this is that the winner in each state, with a particular emphasis on Michigan, will do significantly better in a very tight race than they would if the delegates were divided evenly. It could add up to as many as fifty extra delegates for whoever wins all the close races. And for Bernie Sanders, that could spell the difference between catching up to Joe Biden and potentially regaining some momentum or falling even further behind.

It’s funny how primary delegate math works, eh? But those are the rules of the road and everybody has to play by them.