WASHINGTON - Hillary Rodham Clinton's tenure as secretary of state was supposed to be a central argument for her forthcoming run for president. Her globe-trotting record as the nation's chief diplomat, her role championing women's empowerment and gay rights, and her experience on tough national security issues were all supposed to confer credentials that none of her possible GOP opponents would possess.

But over the last two weeks, with back-to-back revelations that she was working with foreign countries that gave millions to her family's charitable foundation and that she set up and exclusively used her own private e-mail system, that argument has been put in peril.

Instead of a fresh chapter in which she came into her own, Clinton's time as the country's top diplomat now threatens to remind voters of what some people dislike about her - a tendency toward secrecy and defensiveness, along with the whiff of scandal that blotted the record of her husband, former President Bill Clinton.

That side of Hillary Clinton also plays directly into the main Republican argument against her, that she is a candidate of "yesterday" - as Sen. Marco Rubio of Florida recently put it - who comes with decades of baggage the country no longer need carry.

"Part of the reason the story is gaining traction is that it reminds people of what the Clinton White House was like," said American University political science professor Jennifer Lawless. "It reminds people of the scandals, the secrecy, and the lack of transparency that were often associated with Bill Clinton's eight years in Washington."

Clinton was already certain to face sharp questions during a presidential campaign about her handling of the deadly attacks on U.S. facilities in Benghazi, Libya, in 2012. She has never been shown to have any direct role in events leading up to the deaths of the U.S. ambassador and three other Americans, but an inquiry that Democrats call a fishing expedition has been given new life by the revelation that Clinton's e-mails were not immediately given to Congress.

Rep. Trey Gowdy (R., S.C.), who chairs a special congressional committee on Benghazi, has subpoenaed Clinton's e-mails and plans to call Clinton as a witness once his investigation is further along. That will mean a showdown in the middle of a presidential campaign in which Clinton will be trying to reintroduce herself to voters.

Clinton has said nothing about the e-mails beyond a tweet promising to seek to make them public. On Sunday, Sen. Dianne Feinstein (D., Calif.) said Clinton needs to talk in more detail about the issue. "From this point on, the silence is going to hurt her," Feinstein said on NBC's Meet the Press.

The comments, coming from the top Democrat on the Senate Intelligence Committee, are some of the most forceful that Clinton has faced on the issue from a prominent member of her party.

Clinton's problems at the State Department also make it easier for Republicans to connect her to what they see as President Obama's shaky foreign policy and his broken promise to operate the most transparent administration in history.

Former Florida Gov. Jeb Bush, who is weighing a 2016 bid, cast Clinton's reliance on private e-mail as a serious security risk.

And while Clinton remains the overwhelming favorite for her party's nomination, some Democrats last week were more open about their misgivings about her candidacy. On Friday night in New Hampshire, former Maryland Gov. Martin O'Malley, who might run against Clinton, for the first time criticized her use of the private e-mail account, saying that "openness and transparency are required of governing in the modern age."

For Clinton, the State Department years were a kind of protective cocoon from partisan politics, even though she was a visible member of a Democratic administration that was doing regular battle with congressional Republicans.

Clinton was rarely called upon to take public positions on partisan issues. Her history as a politically active first lady, senator, and failed Democratic candidate for president were rarely mentioned in day-to-day news coverage of her trips and priorities as secretary.

Clinton posted a Twitter message Wednesday night saying she wants the public "to see my e-mails." She said she has asked the State Department to review them for release. That review could also establish whether she broke any rules about the handling of sensitive information.

The e-mail arrangement meant Clinton's work e-mails were being routed through a private server located in her Chappaqua, N.Y., home, and were not being archived by the government as now required. She handed over 55,000 pages of e-mails upon the State Department's request last year, more than a year after she left her post.

Clinton has not explained the reason for the unorthodox arrangement, and her husband declined to weigh in on Sunday. "I'm not the one to judge that. I have an opinion, but I have a bias," Bill Clinton said in response to a reporter's question during a Florida appearance, according to Bloomberg Politics.

Obama said in an interview with CBS on Saturday that he did not know about Hillary Clinton's use of private e-mail until reading news reports last week.

White House officials communicated with Clinton on her private account, and it is not clear that any White House official flagged the practice as a potential problem.

The e-mail revelation came after the Bill, Hillary and Chelsea Clinton Foundation acknowledged in February that it had accepted a foreign-government donation in 2010 without submitting it for an ethics review, as required in a 2008 agreement with the Obama administration.

The 2008 agreement had been reached to avoid the appearance of conflicts of interest while Hillary Clinton was secretary of state. Under the agreement, the foundation was to submit any donation from a foreign government that had not previously given money to the foundation.