Kos revisits an indisputably good idea: Demote Iowa and New Hampshire from the primary process. As an alternative, he suggests regional primaries that rotate every election. Maybe. At this point, though, I think the Democrats should turn their primaries into a "ring of fire" type ordeal. Have each day of the primaries involve four states that include 1) a key swing state from the Midwest, 2) a key swing state from the Southwest, 3) a reliably liberal but not overly large state, 4) a southern "fringe" state that might be winnable.

So the first primary day would be something like Ohio, Nevada, Maine, North Carolina. Have the next primary day be Michigan, New Mexico, Oregon, Florida. Then whatever.

The details could be tinkered with, obviously. But the goal is Darwinian natural selection—any candidate who emerges victorious will have to be somewhat appealing to swing voters, even if that candidate doesn't, in fact win all the swing states. And the inclusion of the liberal state ensures that candidates don't drift too far to the right. You won't get a perfect candidate out of this (since candidates will still just focus on particular subsets of each primary cluster), but you're more likely to get a sturdy national contender than you are by having someone win Iowa, New Hampshire, and then use that inevitability to sweep everything else.