Why Hillary Clinton’s delegate lead over Bernie Sanders is bigger than it looks

But here's the thing: Whether or not Clinton wins Ohio doesn't really matter.

It's important to remember that the Democrats, unlike the Republicans, don't allocate delegates on a winner-take-all basis. When Donald Trump won South Carolina with a plurality of the vote, he got all of the state's 50 delegates, a total that right now constitutes more than half of his lead. There are no states like that on the Democratic side. There are some variations in how the states divvy up their delegates, but they're proportionally distributed from now until the primary is over.

Which is why the 2008 daily delegate totals looked like this.

https://img.washingtonpost.com/wp-apps/imrs.php?src=&w=1484

As Clinton tried to play catch-up with Barack Obama, he would get some delegates every time she did. The only times she made big gains against him was in states she won by a wide margin. But the proportional delegate system kept Obama steadily out of reach.

It's worth comparing Obama's 2008 lead in the delegates to Clinton's. Clinton, by virtue of huge margins of victory in Mississippi, Alabama and Louisiana, has a much bigger lead than Obama did at this point -- or than Obama did at any point. (The data below excludes superdelegates.)
https://img.washingtonpost.com/wp-apps/imrs.php?src=&w=1484