1. How does Mitt get over the top?

This year the rules for the Republican nominating convention have been changed to tilt more toward awarding delegates proportionately rather than giving all the state’s delegates to whoever wins its primary, no matter how slim the margin. To be sure, some reports have overstated the change; the rules have never been completely winner-take-all across the country, and this year’s changes don’t affect every state. But the changes could be important in a year when national polls continue to point to front-runner Mitt Romney’s difficulty in attracting more than about 25% support.