Hillary Clinton is still trying to have it both ways on trade: supportive of organized labor but unwilling to fully abandon a deal she helped negotiate.

Clinton would only think about voting for a bill giving Obama fast-track authority to negotiate a Pacific trade deal if she was sure a related bill helping affected workers would also pass, a campaign spokesman said Thursday. But the major question facing Senate Democrats right now is just that — whether they can trust that both bills will be signed into law.

The fast-track rules are known as TPA, which stands for Trade Promotion Authority.

The bill providing worker benefits is known as TAA, which stands for Trade Adjustment Assistance

The trade deal Obama is pursuing is called the Trans-Pacific Partnership, or TPP.

"Consistent with her strong support for worker protections, Hillary Clinton said she of course couldn't consider voting for any TPA without confidence that TAA would be extended," campaign spokesman Brian Fallon said. "That said, her focus remains on the substance of the TPP agreement."

While it sounds like Clinton is skeptical of the deal, the 2016 Democratic frontrunner's position is actually a hedge that allows her to claim she was on the right side of her party whether the president gets fast-track authority or not. That's no small matter for a candidate who is getting pressure from her left to be against a trade deal that she advanced and praised as Obama's first-term secretary of state.

Having it both ways

What Fallon didn't say is instructive. He didn't say whether Clinton trusts a promise from congressional Republicans — supported by Obama — that the TAA bill will be passed after TPA.

That's the central question vexing Senate Democrats as they decide whether to send TPA to the president next week or kill it. They will have to vote on TPA before the fate of TAA is clear. Because she's not in the Senate, Clinton doesn't have to vote. That gives her flexibility, no matter the outcome.

If the White House deal with GOP leaders works — and both bills pass — Clinton can say she would have supported it because both elements made it into law. If the Senate rejects TPA with TAA hanging in the balance, Clinton can say that was the right choice because the guarantee of TAA passing wasn't strong enough.

Fallon did not reply to an email asking whether Clinton would actually vote "no" on TPA if she were still in the Senate.

Ducking, dodging, and weaving

The best indication of how much trouble Clinton is having with the trade issue was her response earlier this week to the question of whether the president should have fast-track negotiating authority. Every president seeks that power, and Congress usually gives it. Moreover, Clinton was a huge proponent of trade, and the TPP deal specifically, as secretary of state.

But when she was asked about the trade authority on Monday in New Hampshire, Clinton called it a "process issue" that was not as important to her as the substance of the TPP deal.

The second-leading candidate for the Democratic nomination, Vermont Senator Bernie Sanders, is a vocal opponent of TPA and TPP, as is organized labor. Clinton can ill afford to alienate the nation's big unions or working-class voters who are wary of trade. The unions spend heavily during campaign season, and they have threatened to cut off congressional Democrats who oppose them on trade.