When asked if Mrs. Clinton’s decision would affect Mr. Biden’s own deliberations about the race, Mr. Biden’s longtime strategist, Joe Slade White, answered, “Of course it would.” But, he said, “That doesn’t mean it would make him not do it.”

But others say Mrs. Clinton has plenty of time, especially since she is doing just enough to keep potential supporters at the edge of their seats (Exhibit A: her video for the Human Rights Campaign supporting same-sex marriage two weeks ago).

Those who are most connected to her exhaustive network of political financiers — some of whom remained in her orbit with plum invitations to official diplomatic soirees — say its most important members will make no move until she gives the signal.

“I’ve talked to a number of donors who are willing to write whatever they’re permitted to write to a presidential campaign, and certainly to write very big money to any sort of ‘super PAC’ that would be supportive of her,” said Harold M. Ickes, a senior adviser to Mrs. Clinton’s 2008 campaign and the president last year of the super PAC that supported President Obama, Priorities USA Action. “They’re just saying to me, ‘Whenever she’s ready, we’re ready.’ ”