More than two dozen former top U.S. officials are urging Congress to support a sweeping Pacific trade agreement that could get a vote sometime early next year. 

The group of 26 former Asia-focused trade, economic, diplomatic, security and intelligence officials sent a letter on Wednesday to House and Senate leadership calling the Trans-Pacific Partnership (TPP) a “concrete manifestation of our rebalancing strategy toward Asia and a strategic necessity for the United States.”

{mosads}But the expansive agreement, completed last week in Atlanta after five years of talks, faces stiff headwinds from congressional lawmakers in both parties.

The White House will be tasked with holding onto the 28 House Democrats who supported fast-track in June. There could be a few other Democratic votes in favor of the TPP, but that number likely remains small amid vast opposition within President Obama’s party.

Then there’s the 190 Republican supporters in the lower chamber who the Obama administration must convince to vote again with the president on the TPP like they did on trade promotion authority. With possible defections from that bloc over TPP’s tobacco provisions, the agreement also may need a few of the 50 who opposed fast-track to support the deal.

Fast-track, a markedly difficult vote, received 218 votes in the House, just enough to pass. The policy allows the trade agreement to go through Congress without amendment.

“Bipartisan support for TPP will ensure that the United States takes advantage of the deal’s considerable benefits and continues to be a global leader on trade,” the former officials wrote to congressional leaders. 

They argue that the Asia-Pacific region is the world’s fastest growing and that by 2030 there will be 3.2 billion middle-class consumers there.

In 2014, exports of goods and services supported 11.7 million jobs in the United States, they wrote. 

“A successful TPP will provide not only a window to dynamic Asian markets, but also a critical boost to American job creation, particularly in manufacturing,” they wrote. 

The letter highlighted new opportunities for U.S. exports to Japan, the nation’s second-leading trading partner “whose markets have long been closed to many U.S. agricultural and manufactured products.” 

The leaders say the TPP will help the United States make a clear statement about “the centrality of the United States in the global trading system.”

“The TPP provides a powerful avenue for continued direct engagement with regional partners and allows the U.S. to more effectively promote a level playing field in Asia that supports and reinforces American interests,” they wrote