One of the oddities of the primary season in that the Democratic and Republican contests take place under different sets of rules. In general, the Democratic contests award delegates proportionately — the number of delegates you win is roughly equal to the number of votes you receive, so long as you clear a minimum threshold (15 percent, generally). The Republicans, by contrast, tend to use winner-take-all rules. So the fine folks at the Monkey Cage decided to look into what would happen if you switched the rules. First, check out the Democrats:

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Because I don’t know how to control the range Excel places on the Y axis, the results look a bit more dramatic than they really are. The takeaway here is that Republican winner-take-all rules would make the contest a bit more competitive, giving Clinton round 70 more delegates, and taking 30-some from Obama. But check out the Republicans:

delegatesrepubs.jpg

Among them, the difference is huge. Shift to proportional, Democratic rules and McCain’s insurmountable lead snaps back to a dead heat with Romney. It’s only under the winner-take-all system that his strategy of eschewing field organizing and eking out victories suffices.

Meanwhile, it’s a bit odd that, for both parties, switching to the other side’s rules would make the race more, rather than less, competitive.

Ezra Klein is a former Prospect writer and current editor-in-chief at Vox. His work has appeared in the LA Times, The Guardian, The Washington Monthly, The New Republic, Slate, and The Columbia Journalism Review. He’s been a commentator on MSNBC, CNN, NPR, and more.