GOP senator moves to weaken Trump's tariff powers in latest sign of Republican rebellion

Sen. Chuck Grassley (R-IA), a longtime political ally of President Donald Trump, scrambled on Thursday to introduce legislation to put new limits on President Donald Trump's powers to unilaterally slap tariffs on foreign goods.

Via CNBC's Carl Quintanilla, Grassley is joining with Sen. Maria Cantwell (D-WA) to push new legislation requiring Congress to authorize all tariffs enacted by the president within 60 days of their issuance.

Congress already has the power to stop Trump's tariffs from taking effect, although it would likely require a veto-proof majority of legislators to get such restrictions passed.

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Grassley's move is just the latest sign of a Republican rebellion against Trump's trade war.

Earlier this week, Sens. Susan Collins (R-ME), Lisa Murkowski (R-AK), Mitch McConnell (R-KY) and Rand Paul (R-KY) joined with all Senate Democrats to vote in favor of rolling back the tariffs that Trump levied against Canada.

It is unclear if House Speaker Mike Johnson (R-LA) will even allow that bill to have a vote on the House floor, however, and Trump would certainly veto it if it came to his desk.

Markets on Thursday crumbled in the wake of Trump's big tariff announcement, with the Dow Jones Industrial Average falling by more than 1,400 points in early trading and Nasdaq dropping by nearly 1,000 points.