House Speaker Paul Ryan's office contended the White House and Congress were on the "same page."
"We have been and continue to be on the same page about tax reform that supports American jobs and American goods," Ryan aide AshLee Strong told NPR's Susan Davis.
That's because Ryan has proposed a "border adjustment" tax that would affect the "corporate tax rates applied to goods and services consumed in the U.S. but not applied to goods and services exported," a Republican Capitol Hill source added.
The plan would allow corporations to subtract export sales when calculating their tax bill, but companies would not be allowed to deduct the cost of imports. Under the current tax code, export sales are taxed, and import costs are deductible.
If Trump is embracing Ryan's plan, it would be a reversal. Just 10 days ago, he told the Wall Street Journal that a "border adjustment tax" was "too complicated."
"Anytime I hear border adjustment, I don't love it," Trump said. "Because usually it means we're going to get adjusted into a bad deal. That's what happens."
Texas Republican Sen. John Cornyn said the plan raises questions.
Spicer brushed aside suggestions that much of the cost would be passed on to American consumers who purchase Mexican-made goods. He argued that cost would be outweighed by the reduction in illicit border crossings.
"What it's going to do is lift up the wages of American workers," Spicer said. "Right now we've got an influx of cheap labor. It's going to put the American consumer back, net-net, to make sure that American workers get lifted up as well."
Back in Washington, after the original comments, Spicer said, "I don't think our job right now is to roll something out and/or be prescriptive. It's to show that there are ways the wall can be paid for. Full stop."
He added that he was trying to address "questions about how the president could pay for the wall."
He said, "The idea is to show that generating revenue for the wall is not as difficult as some might have suggested." But "there's nothing to roll out, so the idea of asking for details on something, we're not there yet."
Spicer also suggested that building the border wall would produce savings elsewhere in the federal budget.
"I think we're going to save additional money that we would have had to spend on tracking down illegal immigrants and on immigration," Spicer said. "So it's actually a huge win for the American taxpayer and for American security when you look at the kind of plan that's coming to fruition right now."
Trump actually wants to increase spending on immigration enforcement. In addition to the wall, he has ordered the hiring of 15,000 new Border Patrol and immigration officers and the construction of new detention facilities.
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