Both senators have concerns over how the department will handle phaseouts of clean energy tax credits from the Biden-era Inflation Reduction Act for wind and solar projects that were rolled back in Trump’s One Big Beautiful Bill Act, which allows a one-year window for projects to start and still be eligible. Curtis and Grassley played a major role in crafting the gradual transition.

However, a Trump executive order issued days after the law’s passage last month raised questions about whether the Treasury could speed up that timeline to appease conservatives who wanted a more immediate phaseout. Grassley cited the need for an “orderly phaseout” for businesses.

“Until I can be certain that such rules and regulations adhere to the law and congressional intent, I intend to continue to object to the consideration of these Treasury nominees,” Grassley entered into the Congressional Record.

Curtis has similar anxieties, according to a source familiar with the matter, particularly that the order may seek to nullify language from Trump’s signature tax cut law.

It’s not uncommon for senators to use nominees as bargaining chips, but it is far less common for members of the president’s own party to do so. The nominees are but three of dozens pending confirmation in the upper chamber, creating major tension between Republicans and Democrats last week before the Senate embarked on its August recess. The GOP majority is weighing rules changes upon returning in September that could more easily allow them to confirm nominees in the face of Democratic stonewalling.

Trump’s executive order states that its purpose is to “eliminate subsidies for unreliable ‘green’ energy sources like wind and solar” and directs Treasury Secretary Scott Bessent to “terminate the clean electricity production and investment tax credits for wind and solar facilities.”

However, it’s possible the holds from Grassley and Curtis, which would require additional procedural votes on the trio of nominees who were advanced from committees earlier this year along party lines, may be rendered moot.

TRUMP’S PRESSURE TO EASE NOMINEE BACKLOG FORCES SENATE INTO RARE WEEKEND SESSION

Grassley cited the Treasury’s Aug. 18 plans to release rules and regulations for the tax credit phaseouts, at which point the senators could withdraw their holds. The Senate is on recess until Sept. 2 and will not conduct business before then.

“What it means for a project to ‘begin construction’ has been well established by Treasury guidance for more than a decade,” Grassley said. “Moreover, Congress specifically references current Treasury guidance to set that term’s meaning in law. This is a case where both the law and congressional intent are clear.”