A spokesman for the antiabortion movement, Mr. Keyes ran a morality-based campaign that gained few delegates but nonetheless built a nationwide coalition of followers.

The focus on viability is designed to weed out small, divisive factions from gaining delegates to disrupt the national convention.

The candidate must receive at least 15 percent of the votes to gain delegates.

"So far, you've fallen short yourself, George; remember, we gained delegates on the second ballot."

Such a vote would have to go to Mr. Brown, it said, because only he seemed likely to get the 15 percent needed to gain delegates.

Alpert gained greater recognition and several delegates following revelations on Richard Blumenthal's Vietnam record.

Following the final primaries on June 3, 2008, Obama had gained enough delegates to become the presumptive nominee.

On the second ballot, Blaine received 375 (gaining delegates from Edmunds), Arthur 274.

On March 8, the six Democratic candidates split the results in 20 states, with Gov. Michael S. Dukakis of Massachusetts gaining the most delegates.

Dark horse candidates were chosen in order to break deadlocks between more popular and powerful prospective nominees that blocked each other from gaining enough delegates to be nominated.