The Supreme Court appeared deeply concerned Wednesday with President Donald Trump’s reliance on a vague federal law to impose global tariffs, with several members of the court’s conservative wing picking apart the administration’s position in a case that could have sweeping implications for the economy and presidential power.

During more than 2 and a half hours of argument in one of the most important economic cases to reach the high court in years, Chief Justice John Roberts and several of his fellow conservatives pointedly questioned the administration on its contention that it has the power to levy the tariffs and that the duties are a form of “regulation” of imports rather than a tax ultimately paid by American consumers.

If it breaks with Trump on tariffs, it would be the first time the 6-3 conservative court has done so in a major argued case since the president returned to power in January. In case after case, the court has blessed the administration’s boundary-pushing policies on immigration, spending and independent agencies.

Here are the key takeaways from Wednesday’s arguments:

Roberts and Barrett pile on fast

The arguments were lengthy, but some signals about how the justices are thinking about the appeal were clear almost immediately.

Roberts, who is without a question a key vote, noted that the 1970s law the administration has relied on to levy the tariffs has never before been used for that purpose, and also poin