Hillary Rodham Clinton's preparation for Tuesday’s first Democratic debate has fallen into two categories: attempts to address perceived liabilities in substance -- and efforts to deal with the perception she's fallen short on style.

She aligned herself with liberal challengers in opposing both the Keystone XL pipeline and President Obama’s Pacific trade deal to head off attacks from the left. She made fun of herself on Saturday Night Live and gave interviews to outlets – a Lena Dunham video newsletter, a BuzzFeed podcast focused on African-Americans – chosen to showcase herself in a new, hip light.

But Clinton’s shifting record and reputation as a programmed candidate in a year of breakout political stars admired for their “authenticity” will still be big obstacles for Clinton in the debate and in the election. Even her effort to deal with them is likely to provide an avenue of attack for her challengers.

Her top challenger, Sen. Bernie Sanders (I-Vt.), has already said that voters can judge for themselves whose record on the Trans-Pacific Partnership trade deal is more consistent: his long opposition on worker- and job-protection grounds, or her declaration last week that despite supporting the deal when she was secretary of state she now finds it lacking.

It's a glimpse of the sort of swipes she might expect at tonight's faceoff. They include:

The flip-flop problem. Keystone and the TPP, both of which became liberal yardsticks after she had worked to get both projects underway while she was in office, are the latest examples of what opponents can easily label as a political lifetime of shifting positions.

Clinton herself has said she “evolved” to support same-sex marriage. And while she gave the first major speech of this campaign on the problem of over-incarceration, her rhetoric about the Black Lives Matter movement has become more sympathetic as the campaign continued.

The primary contest is tugging Clinton to the left on environmental, labor and regulatory issues, including proposals just last week to toughen controls on Wall Street. But her timing will allow Sanders and former Maryland governor Martin O’Malley to say she has a finger to the political wind.

The authenticity problem. Underlying the specifics of Clinton's shifts on policy are questions about her political compass. For many liberal Democratic voters and activists, Clinton's lean to the left is suspect after a career in which she thrived most often as a pragmatic centrist. Voters tell pollsters they do not find Clinton trustworthy, even if a majority of Democrats also say they could envision voting for her.

Sanders's surprise success is based largely on a sense among supporters that he stands for the same things he has always stood for, a true north that Clinton has struggled to show for herself. A mainstay of her campaign is an argument that from her very first job, Clinton has been a fighter and an advocate. But the narrative has done little or nothing to stem a drop in support for Clinton in New Hampshire and Iowa, the early voting states where she has spent the most time and money showcasing that image.

The been-there done-that problem. References to Clinton's long and varied career can highlight experience and competence -- but also remind voters and debate viewers of how long she has been a part of the American public consciousness.

Her potential to make history as the first woman to become president will be on display alongside four male opponents, but so will her quarter-century in political life. In a season when voters of both parties are rewarding newcomers and anti-establishment candidates, Clinton is a former first lady, senator and secretary of state, as well as a previous presidential candidate.

The accomplishment problem. Clinton's legislative successes as the junior senator from New York were never huge and are now a decade old. Despite sky-high approval ratings as secretary of state, Clinton has no major peace treaty or other traditional marker of diplomatic success to her name. She helped initiate the talks that eventually produced a nuclear deal with Iran after she had left office and helped broker a lasting ease-fire in the Gaza Strip, among other specific accomplishments.

Clinton has now disavowed the TPP, which had been considered one of the few other clear successes of her tenure.

Her influence tended to rely more on her advocacy for women and girls and her own star power, which she lent to overlooked causes such as clean-burning stoves for the developing world.

Her record of backing military action in Libya and the surge of U.S. forces in Afghanistan, as well as her current support for a no-fly zone in Syria, will allow her liberal opponents to paint her as a hawk or interventionist. Opponent Jim Webb, a former senator from Virginia, with its many military bases and economic dependence on the defense industry, is the only debate opponent who appears more hawkish than she.