Hillary Clinton has told a German magazine the United States should follow Germany, where Angela Merkel is chancellor, and have a woman in charge.
She stopped short of saying, however, that it should be her.
"We are way behind you in Germany on this," the former secretary of state told Stern magazine in an interview to be published in its next edition on Wednesday.
"Of course I want the USA to have a woman leader soon as well and I will do all I can for that to happen, though I don't know yet if it will be me," she said.
Mrs Clinton, a former senator and the wife of the former US president Bill Clinton, is widely expected to run for the White House in 2016.
Mrs Clinton, meanwhile, said she understood Germany's anger at revelations that the US National Security Agency had listened in to Ms Merkel's mobile phone as part of its large-scale surveillance of electronic communications in Germany.
"I would be as furious as the Germans are. I would demand that my friend and ally stop eavesdropping immediately," Mrs Clinton said, adding however that a 'no-spy agreement', as demanded by some German politicians, was not a practical option.
"It wouldn't be flexible enough," she told Stern of such an agreement. "I don't think a written treaty is the right way to do it - and it shouldn't be necessary in the first place."