Even as members of his own party weigh whether Congress has the authority to push back on his trade actions, President Donald Trump on Tuesday slapped new tariffs on solar panels and washing machines.

“It will provide a strong incentive for LG and Samsung to follow through on their recent promises to build major manufacturing plants for washing machines right here in the United States,” Trump said during an Oval Office signing event, adding the actions “uphold a principle of fair trade and demonstrate to the world that the United States will not be taken advantage of anymore.” That echoes a major theme of his 2016 campaign and the first year of his presidency.

But Republican Sen. Ben Sasse of Nebraska issued a statement on Tuesday warning the president against the new tariffs, and other GOP senators openly mused about seeking ways to insert themselves into a testy trade debate.

“Here’s something Republicans used to understand: Tariffs are taxes on families,” he said. “Moms and dads shopping on a budget for a new washing machine will pay for this — not big companies.”

Senate Republicans also discussed Trump’s trade stances at length during Tuesday’s weekly GOP policy lunch. Among the biggest issues raised were the possible withdrawal from the North American Free Trade Agreement and the solar panel and washing machine tariffs.