Republicans brought a simmering debate over the cost of President Donald Trump‘s agenda to the Senate floor, raising a wonky but consequential question that could greenlight trillions in new spending.

Senate Majority Leader John Thune (R-SD) raised a point of order Sunday afternoon, just after clerks finished reading all 940 pages of Trump’s tax agenda. The motion was intended to establish that Sen. Lindsey Graham (R-SC), the Budget Committee chairman, can set a “current policy baseline,” a novel accounting method that treats extending Trump’s 2017 tax cuts as cost-free, but it was promptly challenged by the Democrats.