President Trump, shortly after issuing his first veto in March. Photo: Alex Wong/Getty Images

This week, President Trump threatened to impose a 5 percent tariff on goods entering through the southern border if Mexico cannot curtail the flow of undocumented migrants into the U.S. by the comically short deadline of June 10 – and Senate Republicans are not thrilled. At a closed-door lunch on Tuesday, GOP lawmakers ripped into White House deputy counsel Pat Philbin and Assistant Attorney General Steve Engel, threatening a Trump administration first: a veto-proof majority in the Senate that would void the tariffs.

Speaking to reporters after the lunch, at least five Republican senators expressed their frustrations with Trump’s fast and loose application of tariffs. Mitch McConnell said that “there is not much support in my conference for tariffs, that’s for sure.” Senator James Lankford delivered a slightly more colorful statement: The White House “is trying to use tariffs to solve every problem but HIV and climate change.” An unnamed senator put it more curtly, according to The Hill: “Nobody was supportive.”

Meanwhile, the administration is considering a declaration of a second national emergency in order to apply the Mexico tariff. But as Politico notes, the premise of a tariff emergency would be far more controversial than the one called for the border crisis, “given the strong free-trade inclinations of the Senate GOP.” In March, 12 Republicans joined a resolution of disapproval to block Trump’s first emergency declaration, but Trump vetoed the measure.

Senator Ron Johnson of Wisconsin, who supported the first national emergency, said on Tuesday that “the administration ought to be concerned about another vote of disapproval on another national emergency act, this time trying to implement tariffs … This would certainly give me great pause.” After all the president’s norm-breaking behavior and reputation-shattering statements, it might be a tariff that causes Republican senators to cross the aisle for a vetoproof majority. But such an act of bipartisanship would still be difficult to achieve, considering the 20 senators and 50 House Republicans necessary to lock in such a vote.