"Let's take the lemons and turn it into lemonade," Clinton told more than 700 supporters at the Iowa State Fairgrounds, addressing the controversial Trans Pacific Partnership trade proposal that has splintered Obama from House Democratic leader Nancy Pelosi and rank-and-file Democrats.

Courting Iowa voters, Clinton sought to address Democratic opponents of the trade legislation, including liberals and labor unions, who have said the Obama-backed plan will cost U.S. jobs. The agreement has not been finalized or submitted to Congress.

Clinton sought to distance herself from Obama, urging him to listen to Pelosi and Democrats "to make sure we get the best, strongest deal possible. And if we don't get it, there should be no deal."

"I have held my peace because I thought it was important for the Congress to have a full debate without thrusting presidential politics and candidates into it," Clinton said at a house party in Burlington, Iowa. "But now I think the president and his team could have a chance to drive a harder bargain."

She urged Obama to be focused on a path forward and in "getting to what works."

Clinton said she had some concerns with the deal. She questioned the dispute-resolution process, saying it should not only be done behind closed doors and it "has to listen to other voices beyond corporate interests." She also said that drug companies that would do well under the deal should be required to negotiate drug prices in America with Medicare.

One of her main Democratic rivals, Sen. Bernie Sanders, said that wasn't good enough. "Is she for it? Is she against it?" Sanders told reporters in Indianola. "Those are your two options."

The White House and Republican leaders in Congress now face long odds in reviving the legislation after congressional Democrats helped defeat a job retraining program in a blow to Obama's attempt to secure so-called fast track authority. Without the authority to negotiate trade deals that Congress can approve or reject, but not amend, the president would face difficulty in securing the Asia trade deal after years of work.

Pelosi decided to side with House Democrats and oppose Obama's plan, saying it required "a better deal for America's workers."

Clinton appeared to seek middle ground, saying while some support the deal and others vehemently oppose it, "I kind of fall in the group that says `what's in it?' And `let's make it as good as it can be, and then let's make a decision.'" She said Obama had an "amazing opportunity" to negotiate better terms that included worker protections, wages and national security provisions that she said she would seek in a final deal.

Clinton said any deal should include the scuttled program to help retrain workers.

Trade has emerged as an early divider within the Democratic primary. Sanders, who made several campaign stops in Iowa on Sunday, again called on Clinton to oppose the measure.

"I kind of think people would prefer to hear what your position is - are you for it or against it? Rather than passing the buck and saying well, in a sense, I don't have a position. That is not leadership," Sanders said.

Former Maryland Gov. Martin O'Malley has also opposed the deal and likened it to the North American Free Trade Agreement signed into law by President Bill Clinton in 1993. In a statement that did not mention Hillary Clinton by name, O'Malley said Democratic leaders should "step up and urge Congress not to fast track this bad trade deal. We've seen this movie before with NAFTA - a bad trade deal that devastated communities across the country and cost a million American jobs."

The Obama administration expressed confidence Sunday that Congress will approve the trade provisions. Republican leaders generally support Obama's proposal and have suggested they may try to revive the bill as early as this week. "Republicans delivered," said Rep. Paul Ryan, R-Wis., on "Fox News Sunday." `'The question is, are the Democrats going to do this to their president."

While Clinton has refused to take a position on TPP since announcing her candidacy, she called the pact the "gold standard" of trade agreements while serving as secretary of state. Criticism came quickly on Sunday from Republican National Committee spokesman Michael Short.

"By waffling on a trade deal she helped negotiate and once called a "gold standard," Hillary Clinton continues to show why voters overwhelmingly see her as dishonest and untrustworthy," Short said in a statement.

Clinton was spending most of the weekend in Iowa after formally launching her campaign in New York City, seeking to build an organizational edge in the state that tripped up her first presidential campaign against Obama. Sanders was campaigning across the state and former Virginia Sen. Jim Webb, who is exploring a potential Democratic bid, also was holding events in Iowa on Sunday. O'Malley held a day's events in the state last week.