If she wins, President Hillary Clinton's troubles would start before she is even sworn into office.
Most Americans don't trust her. Many lawmakers vow not to work with her. One already has floated the idea of impeachment. Republican congressional investigations are likely, adding to a new FBI investigation involving her personal e-mail system.
How could she govern? Clinton's three decades of experience in government, punctuated by e-mails providing revealing looks at how she operates behind the scenes and interviews with people who have worked with her or against her give some clues as to how she'd work even in such a hostile environment.
She does all of her homework and wants to know everything. She can compartmentalize her feelings enough to work with enemies if necessary. She's more willing to socialize with members of Congress than President Obama has been. She relies on staff, sometimes even for personal things. She also can be very insecure, keeps to a select few advisers, doesn't trust the media and worries constantly about her privacy.
One sign of how she might operate: As a senator from New York immediately after leaving the White House, Clinton earned a surprising reputation for working with Republicans on Capitol Hill.
In her first speech as senator, Clinton said she'd learned from her unsuccessful effort as first lady to pass a national health care law. "I learned some valuable lessons about the legislative process, the importance of bipartisan cooperation and the wisdom of taking small steps to get a big job done," she said.
Clinton worked with Sen. Lindsey Graham, R-S.C. — who helped manage the impeachment case against President Bill Clinton — to allow National Guard and reserve troops to buy insurance policies in Tricare, the military health care system.
Republicans and Democrats expect that she would do the same as president — meeting with lawmakers on their home turf on Capitol Hill and inviting them to the White House and Camp David.
"She will make it a significant part of her outreach to Congress by spending time with members, cultivating the members," said Rep. Adam Schiff, D-Calif.
"I think she will be more in tune to the needs of Congress than Obama has been," said Ken Duberstein, who served as President Ronald Reagan's chief of staff in his second term. "She'd treat Congress as more than an adversary."
Other GOP voices are pushing for tougher stands against Clinton's presidency.
Rep. Mo Brooks, R-Ala., has already suggested impeachment hearings against her. Sen. John McCain, R-Ariz., said he would try to block any Clinton Supreme Court nominee. Sens. Ted Cruz, R-Texas, and Richard Burr, R-N.C., said the Senate might leave the nation's high court with only eight members if Clinton were elected. And Republicans are eager to launch more investigations.
"It's a target-rich environment," House Oversight Committee Chairman Jason Chaffetz, R-Utah, told the Washington Post.
Yet Rep. Steve King, R-Iowa, an outspoken conservative who supports Donald Trump, said he could work with a President Clinton. "I've sat across the table with Hillary Clinton eye to eye, and when you're working outside of staff and outside of the press she is somebody I can work with," he said this summer.
At the same time, Clinton would face competing pressures from her own party.
A handful of moderate Democrats from more rural states facing re-election, including Sens. Heidi Heitkamp of North Dakota and Joe Manchin of West Virginia, will want her to advocate a more centrist message.
Yet Sens. Elizabeth Warren, of Massachusetts, Bernie Sanders, independent of Vermont, and Chuck Schumer of New York, who is expected to become Senate Democratic leader next year, would be pushing Clinton to the left, pulling her away from the middle and compromise with the Republicans.
"Whatever reasons they have for mistrusting her … there's nothing she can do to persuade them through words," said William Galston, a former adviser to Bill Clinton who's now a Brookings Institution fellow. "It has to be through deeds."
If her public skills are well known, her private behavior also has been laid bare by the release of thousands of e-mails that offer signs of how she'd govern.
She seeks additional information, accepts unsolicited advice and wants to be more involved. But she is also worried about being left out and has a hard time apologizing.
Six months after the news of her private e-mail system became public, for example, Clinton was still having trouble speaking about her actions. "Everyone wants her to apologize. And she should," top adviser Neera Tanden said in one leaked e-mail. "Apologies are like her Achilles' heel."
Jonathan Allen, co-author of the book "HRC: State Secrets and the Rebirth of Hillary Clinton," described her as "very secretive" with an inner circle that is extremely insular. "She pays a lot of attention to the details of every plan … meaning her staff has to be on its toes at all times," he said. "But even as she keeps information close to her vest, she also understands the need to have buy-in from various stakeholders to get things done."