WASHINGTON — The Obama administration has revealed its trade pact with Pacific nations, a sweeping and controversial deal igniting fierce opposition from President Barack Obama’s Democratic allies.

The Trans-Pacific Partnership trade agreement published on Thursday has been a long-time coming, and with a brutal political fight on the horizon it could be longer still before states ever reap its touted benefits. From agriculture to intellectual property, the pact among the United States, Canada, Mexico, Japan and eight other Pacific nations affects a huge array of commodities.

It promises new markets and millions of new consumers for, say, cotton from Texas, wine from California and pork from North Carolina as tariffs and trade barriers are lowered for nations around the Pacific Rim. And it offers assurances about jobs, labor protections and the environment.

Yet the agreement has to run a gauntlet of congressional skepticism going into the 2016 elections, as well as the sluggishness of a political system where personality and deep ideological division have been roadblocks.

“It eliminates 18,000 taxes that various countries put on American goods,” Obama wrote in a blog post on Medium. “When it comes to Asia, one of the world’s fastest-growing regions, the rulebook is up for grabs. And if we don’t pass this agreement — if America doesn’t write those rules — then countries like China will.”

The Trans-Pacific Partnership pits Obama against Democratic presidential contenders Bernie Sanders and Hillary Clinton, who supported the negotiations as secretary of State but has since turned against the deal. Sanders asserts it would expose American workers to competition with low-wage foreign labor.

The deal puts congressional Republicans, who have supported the negotiations, in the position of voting to give a victory to the president or going against business allies who want a trade pact.