Back in the days of Eisenhower and Stevenson and Humphrey and the Kennedys and Johnson and always before that. That is why what matters is how many delegates a candidate has, not what states the candidate wins. A candidate with a relatively small but significant enough number of delegates can actually have a lot of power over who runs in the end.
Remember, between February 5 and the convention, a lot of nasty information could emerge about the presumed "winner" of the primaries. The whole contest could open up should that happen. In fact, things can even change after the convention.
In 1972, Thomas Eagleton, chosen as the Democratic vice presidential candidate at the convention, dropped out after having to admit he had undergone shock treatment therapy for exhaustion in the past.
http://en.wikipedia.org/wiki/Tom_EagletonHere is an article on the conventions in the early part of the second half of the 20th century:
But these were minor sins compared to the genuinely ugly behavior that later appeared on television. At the 1964 Republican convention, the delegates were roused to frenzy during a speech by Dwight Eisenhower. He invited the delegates to scorn the "sensation-seeking columnists and commentators" of the media -- which they promptly did, live -- and to avoid "maudlin sympathy for the criminal" who counts on the coddling of the courts to ease his way -- and they howled again. They snarled when Nelson Rockefeller defiantly addressed them; they screamed when Ronald Reagan and Richard Nixon spoke on behalf of nominee Barry Goldwater. The nation watched as Goldwater's supporters made a frightening display.
But what the cameras did not see was the Goldwater campaign's efforts to control the demonstrations of the delegates. Already the Republicans knew that what the cameras captured could be devastating to a candidate. They failed to keep the delegates under control in 1964; they would be thoroughly prepared in 1968.
The Democrats had their turn at disaster in 1968. Protest demonstrations inside and outside the convention hall alienated conservative America; the zealous Chicago police alienated liberal and moderate America. The convention could not keep to a schedule; Hubert Humphrey, the nominee, was booed; the incumbent Democratic President was booed. In short, the viewers saw a party mired in chaos. By contrast, the Republican convention at Miami Beach showed the television audience a party that was able to control itself, and by implication govern the nation in a sensible manner. There were no protests, no violence. All the viewers saw were hundreds of pleasant- looking people, all extremely happy about the prospects of voting for Richard Nixon.
Today, both parties have learned their lessons well. They treat the conventions as four nights of free air time and four days of media events, and they manage that time with exquisite care. Campaign films are broadcast, often without any interruption by the broadcasters; spontaneous demonstrations and dances for candidates are carefully choreographed and regulated. Everyone knows who the nominee will be, so there is nothing to be gained by a demonstration for any other candidate. Nothing that detracts in any way from the coronation of the nominees and the distribution of the party's message is permitted. The delegates are not given the option of making any decisions, since decisions are unpredictable and may not fit the happy image of the party. And so the convention becomes even less significant.
http://www.h-net.org/~pol/ssha/netnews/f96/enriquez.htmI remember the chaos and excitement of those unruly conventions. The outcome was probably pretty predictable to the politically savvy, but not to a kid like me. (I actually remember listening to the Democratic conventions on the radio before TV.) Those were exciting events. You could never be sure who the candidate would be until the final vote. We could have a pretty exciting convention this time although I suspect the deals will be made before the convention. We shall see.