One. The exit poll shows some familiar patterns, with Mitt Romney running strongest among high-income and high-education voters. But there are some interesting departures from pattern.

Romney carries all age groups (well, not quite; he trails a bit among the 40-49 cohort but carries the overlapping 30-44 and 45-64 cohorts). In earlier contests young voters broke for Ron Paul and the middle age cohorts went for Rick Santorum. Not in Illinois.