Clinton won by 2 to 1 in Puerto Rico, where she seemed to revel in a weekend of campaigning even as her surrogates fought in Washington to keep her campaign alive.

The victory—coming among Hispanic voters, who are a key constituency in the fall election—underscored a constant source of frustration among Clinton and her supporters: that her strong finish over the past months, with big victories among blue-collar voters, have shown no signs of pushing uncommitted superdelegates into her camp.

“Most Clinton supporters are filled with bewilderment that this is happening,” said Gov. Edward G. Rendell of Pennsylvania. “We are willing to go on, and we understand the inevitability of this, but we are filled with disappointment and amazement: Why haven’t these results caused the superdelegates to come around?”

Clinton, in the interview, in a new television advertisement and in her victory speech in San Juan, laid out why superdelegates should rally around her. She argued that by the time the final vote is counted, she will have more popular votes than Obama, an assertion that has been disputed.

“I think it will be most likely the case in a few days,” Clinton said from San Juan. “I will have won the most votes—more than anyone in the history of the primary process.”