The odd thing about winning a presidential nomination is that winning more points doesn't always get you closer to victory. It's not a football game, where tacking on a few touchdowns helps you come from behind to win. It's a football game in which there are only so many points to be distributed, so the number of touchdowns you need to score is relative to how many there are left.

Bernie Sanders continues to insist that his campaign can amass more pledged delegates than Hillary Clinton by the time voting is done on June 14, and that continues to become less possible. After Clinton's big wins on March 15, the math was basically prohibitive. Since April 5, Sanders has consistently scored fewer touchdowns than he needs to, despite winning more delegates than Clinton on a majority of the days of voting.

As it stands, using delegate counts from Daniel Nichanian and estimates for Tuesday's contests from the Green Papers, Sanders needs to win 67 percent of the remaining pledged delegates in order to pass Clinton by the time voting ends. The vast majority of those delegates — about three-quarters of them — come from California and New Jersey, states where Clinton currently leads. Sanders needs big wins in both of those states or a giant win in California, which would require a stunning shift in the relatively static pattern we've seen so far in Democratic voting.

Sanders needs the light-blue bars on the graph above to be taller than the dark blue line if he is to make headway. Only a few times has he accomplished that.

And all of that is excluding superdelegates. If you include superdelegates, among whom Clinton has a big lead, Sanders needs to win more than 90 percent of the remaining pledged delegates to clinch the nomination. Which means, essentially, that he needs to win every delegate, since winning 85 percent of the vote in Democratic contests earns you 100 percent of the delegate total.

Sanders's argument has been that he will woo superdelegates to his cause at the convention. On Monday, a superdelegate did indeed change his mind — moving from Sanders to Clinton.

Clinton's delegate lead continues to far exceed the lead Barack Obama had over her at the same point in 2008.

This continues to be a far less complicated thing than it's made out to be. Sanders is beating Clinton in states regularly, but that matters only for bragging rights. Since the middle of March, Clinton's lead has been virtually unassailable. After another day of voting when the two split contests and Sanders won more delegates, her lead has only become more impenetrable.