Howard Megdal has this article in Salon, suggesting that the Republican presidential primaries and caucuses might elect a delegate field in which no one candidate has a majority of the delegates. He also suggests that in that case, it is possible that the convention might choose someone for President who did not even run in the presidential primaries. The last major party nominee who had not run in any primaries or caucuses was Hubert Humphrey, the Democratic nominee in 1968. Thanks to both Political Wire and Rick Hasen for the link.
The major party conventions throughtout most of the nation’s history were much earlier, so it was somewhat more practical for the national conventions themselves to make the decision as to whom to nominate. For most of the 20th century, major party presidential conventions were in June. The upcoming Republican convention won’t convene until August 27, 2012.