A small group of protesters shout at senate offices as they demonstrate against the Trans-Pacific Partnership (TPP) trade agreement on Capitol Hill in Washington June 23, 2015. [Photo/Agencies]

The TAA measure was initially combined with the TPA in the Senate in order to boost its appeal for Democrats, most of whom oppose a trade deal. But Republican leaders split the two apart after House Democrats voted against the TAA in order to derail the larger package of trade bills. The Democrats originally supported the TAA measure.

After the fast track cleared both chambers, the TAA bill now returns to the House for approval, where most Democrats who previously opposed the aid program now plan to support it.

House Minority Leader Nancy Pelosi signaled on Wednesday that Democrats would accept the TAA the second time. That would allow both TPA and TAA measures to go to the White House for approval this week.

With TPA in hand, US Trade Representative Michael Froman and his team are positioned to conclude TPP, an agreement covering 40 percent of the world economy, said Scott Miller, a senior advisor at the Center for Strategic and International Studies.