(CNN) Hillary Clinton came out against the Trans Pacific Partnership in an interview Wednesday, breaking with President Barack Obama and his administration, which has forcefully promoted the deal.

In an interview Wednesday with PBS's Judy Woodruff in Iowa, Clinton said, "As of today, I am not in favor of what I have learned about it."

The former secretary of state and 2016 Democratic presidential front-runner cited the "high bar" she set earlier in the year as the reason she was giving the deal a thumbs down.

"I have said from the very beginning that we had to have a trade agreement that would create good American jobs, raise wages and advance our national security and I still believe that is the high bar we have to meet," Clinton said.

She added: "I don't believe it's going to meet the high bar I have set."

Festering question

Clinton's position on the massive 12-nation trade deal -- a staple of the Obama administration's foreign policy in the region -- has been a festering question ever since she launched her bid for the White House.

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Clinton's staff gave the White House a heads-up about her decision before going public, a White House official told CNN.

Earlier this year, Clinton told reporters that she didn't want to comment on the trade deal until it was finalized, something that happened earlier this month.

As secretary of state, Clinton actively advocated for the TPP. In fact, she did so 45 times between 2010 and 2013.

In July, Clinton told CNN that she never worked directly on the deal.

"I did not work on TPP," Clinton said Thursday. "I advocated for a multi-national trade agreement that would 'be the gold standard.' But that was the responsibility of the United States trade representative."

While technically true -- Clinton's State Department was not the lead negotiator on the deal -- the former secretary of state regularly trumped up trade deals, including what would become the TPP.

"We need to keep upping our game both bilaterally and with partners across the region through agreements like the Trans-Pacific Partnership or TPP," Clinton said during a 2012 trip to Australia. "This TPP sets the gold standard in trade agreements to open free, transparent, fair trade, the kind of environment that has the rule of law and a level playing field. And when negotiated, this agreement will cover 40% of the world's total trade and build in strong protections for workers and the environment."

While Clinton has not outright come out against the Trans Pacific Partnership until today, she had signaled over the summer that she was worried about the deal.

'"There are some specifics in there that could and should be changed," Clinton said of the Pacific Rim pact at a June press conference in Iowa. "So I am hoping that's what happens now -- let's take the lemons and turn it into lemonade."

On Wednesday, Clinton argued that those lemons had not, in fact, been turned into lemonade.

"For me, it really comes down to those three points that I made and the fact that we have learned a lot about trade agreements in the past years," Clinton said. "Sometimes they look great on paper."

Clinton specifically cited currency manipulation enforcement, benefits for pharmaceutical companies and impacts on American workers as the reasons she was disapproving the deal.

Departure from the Clinton legacy

It's also a departure from the Clinton legacy: It was President Bill Clinton who, two decades ago, signed the first mega-regional pact: the North American Free Trade Agreement.

The Trans-Pacific Partnership was sold by the Obama administration as a way to right NAFTA's mistakes -- particularly by adding chapters requiring improved labor conditions and implementing environmental standards in the countries involved in the deal.

It was also the economic underpinning of the so-called "pivot to Asia" that Clinton had championed as America's top diplomat.

But the deal is strongly opposed by liberals -- particularly labor unions that fear it would cause the United States to bleed more jobs and wages to countries that pay workers less.

Vermont Sen. Bernie Sanders has highlighted his opposition to the deal on the Democratic presidential campaign trail. And a liberal icon, Sen. Elizabeth Warren of Massachusetts, has hammered its inclusion -- like most other trade deals -- of a provision that would allow companies to challenge whether countries' laws and regulations live up to their international trade commitments.

Former Maryland Gov. Martin O'Malley, her Democratic rival in the presidential race who came out against the TPP earlier this year, quickly blasted Clinton's comments.

"Wow, that's a reversal," he said in Washington. "I believe we need to stop stumbling backwards into bad trade deals and Secretary Clinton can justify her own reversal of opinion on this, but I can tell you that I didn't have one opinion eight months ago and switch that opinion on the eve of debates."

Sanders also took a shot at Clinton for waiting to take a position on the deal.

"To be very frank with you, it would have been more helpful to have her on board a few months ago," he said -- a reference to June, when congressional Democrats were attempting to block trade promotion authority legislation that greased the wheels for the the deal's passage on Capitol Hill.

According to the vice president's office, Joe Biden, who is also considering a run for the White House, backs the deal and will work to get it through Congress.

Skepticism

Clinton first expressed skepticism toward the deal on the campaign trail this summer -- pointing to Warren's criticism as well as the lack of language within the agreement hammering countries like Japan (and China, were it ever to join) for currency manipulation.

Her position aligns Clinton with most Democrats on Capitol Hill.

They first turned on their own party's president when he joined with Republican congressional leaders to push a measure called "trade promotion authority" in June. That legislation -- key to getting other countries to sign off on a final agreement -- allowed Obama to seal the deal and send it to lawmakers for an up-or-down vote with no amendments.

Clinton dismissed that bill as procedural, and said she'd weigh in on the deal once it became final.

Because of the timing -- it will take trade negotiators several months to finish ironing out the final text and translating it into each participating country's language -- the Trans-Pacific Partnership likely won't see votes on Capitol Hill until 2016, meaning the deal will only become more enmeshed in presidential politics.

Most Republicans support the deal -- and, ideologically, back free trade. But front-runner Donald Trump has taken a populist stance, opposing not just the Trans-Pacific Partnership but its forefather, NAFTA -- even saying he'd re-negotiate it.

Former Florida Gov. Jeb Bush said that the plan is "probably a good thing for the country."

"My guess is this deal is going to create real opportunities to open up markets that are fast growing," Bush said at a campaign event. "I haven't looked at the specifics of the deal but my natural inclination is to support trade where barriers are taken down and then we need to fix the things that make it harder for us to compete at home."