The former secretary of state and presumptive Democratic frontrunner for the next White House race was in Kentucky lending her political celebrity to Alison Lundergan Grimes, who has mounted an underdog race to unseat five-term Senator Mitch McConnell, the chamber's top Republican.
The race, in which polls show McConnell with a slim lead, has garnered national attention for possibly playing a role in Republican efforts to take back the Senate.
"Hillary's visit will propel the immense amount of excitement and energy that surrounds Alison's campaign and help translate this strong enthusiasm into votes come election day," Grimes campaign manager Jonathan Hurst said in a statement.
The themes of Clinton's Philadelphia speech last Thursday -- improving opportunities for the middle class, education, workers' and women's rights -- could lay groundwork for a presidential campaign should she choose to run.
Yesterday, while addressing a conference in San Francisco, Clinton delivered a teaser of sorts. Asked about her political future, she told the audience: "I don't want to make any news today."
Clinton, a former first lady, was a US senator for eight years, and it is no secret that she is considering a second presidential run after losing the Democratic nomination in 2008 to eventual White house occupant Barack Obama.
Last month she returned to the presidential proving ground of Iowa, where she lost the first-in-the-nation Democratic caucus in 2008, proclaiming to a crowd: "Hello Iowa -- I'm ba-ack!"
Clinton has reliably outpaced potential Republican and fellow Democratic rivals in polls over the past year.