Republican lawmakers aren’t eager to be drawn into a conflict with the president. But some feel they might have to take action following a growing consensus within the GOP that these new tariffs would amount to tax increases on American businesses and consumers — something that would represent a profound breach of party orthodoxy. Trump has said he would put in place 5 percent tariffs on all Mexican goods as of June 10, rising by another 5 percent a month until October, unless Mexico stops all illegal migration into the United States.

Some White House officials are aware that lawmakers are considering the tactic, but they have not yet decided how to respond. Trump had hoped that threatening to impose tariffs against Mexican imports would lead to major concessions from the Mexican government. But White House officials have not articulated exactly what they want the Mexican government to do, leading to a growing fear among some lawmakers that the White House will push forward with the tariffs when they are scheduled to take effect on June 10…

Aside from a resolution of disapproval, other lawmakers have argued that Congress should pass legislation that would claw back tariff authority from the executive branch. Sen. Patrick J. Toomey (R-Pa.) has introduced a bill that would require congressional approval before a president imposes tariffs under the auspices of national security, and again on Monday made a case for his legislation.