The Trump administration has signaled it is eyeing a border adjustment tax (BAT) to give U.S. exports more leverage over goods imported into the country, but an increasing number of key lawmakers and stakeholders -- including No. 1 trading partner, Canada -- are throwing cold water on the plan.

In one plan floated by House Republicans, a U.S. tax reform package would lower corporate taxes to 20% from 35%. Lost revenue would be recouped under various mechanisms, including a BAT, which could prevent corporations from taking tax deductions on imported products while eliminating taxes on exports. BAT, aka “border tax adjustment, or BTA, is a "destination-based cash flow tax," which involves modifying the income tax structure so that businesses are taxed on where their customers are rather than where they are incorporated.

Some oil and natural gas executives, when pressed last week in Houston at CERAWeek by IHS Markit, danced around whether a BAT would be a positive for the industry. Others were more direct.

The oil and gas industry needs "free and open trade," ExxonMobil Corp. CEO Darren Woods said at the conference. He unveiled a $20 billion spending plan to expand ExxonMobil's petrochemical and refinery activity along the Gulf Coast for products destined for overseas markets. Open borders gig the supply chain, and "you've got to have free trade to make sure you are connecting those dots."

Enbridge Inc. CEO Al Monaco, who oversees the largest energy infrastructure in North America, told a CERAWeek audience that President Trump's "America First" mantra should instead be "North America First." The Calgary-based operator's infrastructure crisscrosses the U.S-Canadian border, and it also wants to ship more natural gas to Mexico through its pipeline network.

"To me, there's no border," Monaco said. "By working together, I believe Canada and the U.S. will become a global energy force."

Norway's Statoil ASA, whose oil and gas projects extend around the world, has created thousands of jobs in the United States, where investments total about $30 billion, CEO Eldar Saetre said.

"Geology rules geography," Saetre told the CERAWeek crowd. By nature, the oil and gas industry is global. "So global cooperation and integrated markets have been and will remain key to make our industry prosper."

GOP Sens. Lisa Murkowski of Alaska and John Cornyn of Texas, who spoke to a CERAWeek audience on Friday, expressed support for a corporate tax overhaul, but they each expressed doubts about the BAT plan.

Under a House proposal being floated, a BAT could generate about $100 billion/year in revenue, based on the size of the U.S. trade deficit. According to the U.S. Bureau of Economic Analysis, the United States in 2016 imported $734 billion more than it exported, excluding trade in services.

"The more I look at it, the more I worry about the assumptions on which they are based," Cornyn, Senate Majority Whip, said of the House analysis. "It is a huge gamble for $1 trillion of tax revenue."

Also of concern are "the politics of it, where you look at cutting corporate taxes but raising the taxes on consumers, through higher price of gasoline coming from refineries, consumer goods, automobiles," he said. Murkowski, who chairs the Energy and Natural Resources Committee, said lawmakers "need to look at it very critically" to ensure House assumptions actually would work.

The two U.S. senators support the president's push to renegotiate the North American Free Trade Agreement (NAFTA) between the United States, Canada and Mexico, which took effect in 1994. NAFTA predates the North American energy renaissance and the opening of Mexico's energy sector.

"It is important to look at the agreement, in particular in the energy space," Murkowski said.

Meanwhile, Canadian Prime Minister Justin Trudeau told a CERAWeek audience on Thursday night that free trade was key for America's No. 1 trading partner. He said a BAT would cause more problems than it's worth during a question-and-answer session led by IHS Markit Vice Chairman Dan Yergin, the conference chair of CERAWeek.

"Anything that creates impediments at the border is something to be concerned with," Trudeau said. As an example, he cited the "level of regulations" for something as innocuous as an auto part. "A part might track back and forth across the border six or seven times. If you're counting on bean counters to track each trip, you're going to hurt the economy." Looking at the audience he said, "You can applaud against the border adjustment tax." It did enthusiastically.

According to a recent analysis by Goldman, Sachs & Co., a BAT could result in lower coal prices and increased competition with global liquefied natural gas (LNG).

"The global gas industry would also benefit from lower costs in U.S. dollar terms, but the change in LNG prices would be limited at first because of the likely modest initial impact of the BTA on U.S. swing suppliers," analyst Damien Courvalin said. The export incentive under a border tax would be muted if domestic gas exporters can't fully monetize tax credits accrued upon export, which initially would be the case for more than half of U.S. export capacity.

"As a result, global gas prices would fall by a smaller margin than coal, and the resulting loss of competitiveness in the fuel mix would cause a decline in demand that would come at the expense of U.S. LNG producers."

Over the long run, he said, corporate activity would allow domestic LNG exporters to monetize in full the export tax credits. An increased incentive to export mostly would offset the impact of lower coal prices, with U.S. export volumes likely to return to their pre-border tax level, Courvalin said.

"In the U.S. market, a modest drop in imports of Canadian gas would be offset by a modest increase in domestic production. Further, U.S. coal prices would trade at a premium to the lower global coal prices and leave the U.S. coal-to-gas switching incentive unchanged. As a result, we believe that a BTA would have negligible impacts on U.S. coal and gas producers and domestic prices. Canadian gas prices would, however, decline 20% relative to U.S. prices."

ClearView Energy Partners LLC observed an interesting phenomenon in the first six weeks of the year that could be related to a potential BAT. The Energy Information Administration has seen U.S. oil inventories rising at record levels, "significantly ahead of typical seasonal patterns," analyst Jacques Rousseau said.

"Notwithstanding the small sample size of five weeks, we believe U.S. companies may be stocking up ahead of a potential U.S. BTA." Part of the increase "could be driven by companies building inventories ahead of a potential U.S. BTA that could potentially increase their acquisition costs of imported crudes," said Rousseau. However, the ClearView thinks the border tax stands only a 25% chance of passage "within the context of tax reform."