John Allen Paulos in his Who’s Counting column at ABC News:
The large number of candidates running for president in both parties splinters voter support. Two unfortunate consequences of this are that good second-tier candidates often quickly fall by the wayside and that not so impressive first-tier candidates are anointed early by the prevailing poobahs and pundits.
A partial solution to the first problem of losing good second-tier candidates prematurely is to use a method different than the standard plurality way of determining winners in the various primaries and caucuses. There are many.
Voters might, for example, rank their favorite candidates, giving, say, three points to their first choice, two to their second, and one to their third, and the one with the highest point total would be the winner. In this way voters could give support to both Obama and Clinton, say, or indulge their secret liking for Ron Paul.
Alternatively, voters might vote for as many of the candidates as they wish and the one with the highest approval percentage would be the winner. The principle of “one person, one vote” might be replaced with “one candidate, one vote.” Scenarios in which, for example, two liberal candidates split the liberal vote, say 32 percent to 28 percent, and allow a conservative candidate to win with 40 percent of the vote would not develop. This method might favor consensus candidates and work against polarizing ones.