“Then it gets interesting,” said Senator Christopher J. Dodd of Connecticut, who is no longer a presidential candidate but retains a voice as a superdelegate.

At the Democratic National Convention in August, there would be 796 superdelegates, assuming the convention sustains the national party’s penalties against Florida and Michigan for moving their primaries earlier in the year. In total, there are 4,049 Democratic delegates; to win the nomination, a candidate must secure 2,025 of them.

The superdelegates are the target of something of an invisible primary as the rival campaigns woo them for endorsements, for the political connections such public backing can bring and for their actual support at the convention, should it be needed. The superdelegates can also be influenced by the primaries. An aide to Senator Barbara Boxer of California said Ms. Boxer would cast her superdelegate vote for the winner of the California primary on Feb. 5.

Superdelegates were created after the 1980 election and were intended to restore some of the power over the nomination process to party insiders, keeping a lid on the zeal of party activists. They immediately came in handy for Mr. Mondale in his 1984 presidential bid, when they gave him a cushion over the upstart campaign of Gary Hart.

Since 1984, they have constituted 15 to 20 percent of the delegates at Democratic conventions, where they have historically supported the front-runner.