A reader writes:
I don't think the results that McCain has been getting are really that unusual for late primaries. It's just unusual that only one of the races should be decided and we should be paying so much attention. Take a look here for Indiana's 2000 GOP primary. McCain, despite bowing out months before, still nets nearly 20% of the vote. It's more likely that discontented voters still show up at the polls to voice their disappointment, while run-of-the-mill voters figure that the race is resolved and just stay home, thereby inflating even a defeated candidates totals.