The Border Adjustment Tax has been the subject of some confusion among the media, politicians, and the public.

Despite President Donald Trump’s seeming endorsement of the measure during his recent speech to Congress, it’s not even clear whether the BAT is part of Trump administration policy. During the election campaign, then-candidate Trump had the opportunity to embrace the policy, but never made it a part of his platform.

At one point, the BAT–which would impose a 20-percent levy on all imports–was touted by administration officials as a way to get Mexico to pay for the proposed wall the United States’ southern border. That was never the case, and that contention has since been dropped by the administration.

To clarify, the Border Adjustment Tax is now, and has been for some time, part of a corporate tax overhaul plan backed by some congressional Republicans, including Speaker Paul Ryan. The idea, first of all, is to raise tax revenues from imports to enable a proposed reduction in corporate tax rates from 35 percent to 20 percent. Supporters say the plan would raise over $1 trillion in ten years, enough to pay for the rate drops.

Beyond the dollars and cents of the plan, the proposal would dramatically change how and where businesses are taxed. It would partially transfer the focal point of taxation from production to consumption. Many countries around the world employ similar tax schemes, and supporters say that US divergence from the global pattern puts domestic businesses at a competitive disadvantage.

But the plan faces stiff opposition, including from within the Trump administration itself. Recent reporting from the Washington Post indicates that White House strategist Stephen Bannon and senior adviser Stephen Miller back the plan, while Treasury Secretary Steve Mnuchin and National Economic Council Director Gary Cohn “have raised concerns” about it. A number of Senate Republicans have also said they would block any attempt to create a tax on imports.

The BAT would create winners and losers among US businesses, and the potential losers are starting to raise their voices in protest. Exporters like aircraft manufacturers could benefit from the BAT while retailers would see their costs and prices rise, triggering a potential loss of revenue.

“The Border Adjustment Tax proposal will have a disproportionately negative impact on US retailers, who employ one in four Americans,” said Everett Gallagher, senior vice president and treasurer of Abercrombie & Fitch. “We are hopeful that Congress can implement a tax reform plan that helps businesses of all sizes without increasing costs to consumers or jeopardizing retailing jobs.”

“We believe the BAT tax would significantly increase our corporate taxes,” said Mike Watts, Vice President of Tax at Big Lots. “which would limit our ability to make capital investments, hurt our associates and be bad for our customers.”

US manufacturers that import some of their inputs would also feel the bite of BAT, noted Sally Hughes, CEO & Founder of Caster Connection, Inc. “Global supply chains are essential to American manufacturers,” she said, “and a Border Adjustment Tax will drive up the price of many products, like those from my company, which are assembled here in the United States by American workers.”

Several Republican Senators have expressed skepticism of the BAT, enough scuttle a bill if it comes down to that. Senator Susan Collins of Maine “sees problems” with the proposal, according to published reports. Senator Tim Scott of South Carolina was quoted in The Hill as saying, “It’s going to be very difficult to get it through the Senate,” adding that consumers will be paying the price for the new tax.

And Senator David Perdue of Georgia told CNBC: “What drives us to the Border Adjustment Tax, according to the people in the House, is the fact that we need it to pay for these other tax changes. I personally don’t subscribe to that theory.”

Meanwhile, Senator Ron Wyden of Oregon, the ranking Democrat on the Senate Finance Committee, summed things up in a speech last week when he said that when an issue provokes so much disagreement among Republicans “it usually promises the movie is not going to end well.”