Hillary Clinton has fed speculation that she might run for the White House in 2016 by telling an audience in Canada that she would like to see a woman president in the United States in her lifetime.
"Let me say this, hypothetically speaking, I really do hope that we have a woman president in my lifetime," Mrs Clinton told a private audience in Toronto.
"And whether it's next time or the next time after that, it really depends on women stepping up andsubjecting themselves to the political process, which is very difficult."
Mrs Clinton, a Democrat who was secretary of state under President Barack Obama, a former senator from New York and is the wife of former President Bill Clinton, is said to be undecided whether to seek the presidency in 2016.
Many Democrats and Republicans in the United States are expecting her to run, although the 65-year-old Mrs Clinton has said she needed to rest after four years as a globe-trotting secretary of state.
Polls have indicated she is far and away the most popular potential Democratic candidate for 2016, and that most Americans would prefer her to several possible Republican contenders.
Mrs Clinton picked up an endorsement on Tuesday from Missouri Senator Claire McCaskill, who announced she is supporting a group encouraging Mrs Clinton to run for the White House.
Last week Clinton started her official Twitter account, describing herself as, among other things, a "wife, mom, lawyer, women &kids advocate."
She alluded to her future as "TBD" - to be determined.