Yesterday, amid the media storm engulfing HHS Secretary Tom Price regarding his private, taxpayer-funded travel, a big new potential opponent of the embattled Secretary emerged: Sen. Chuck Grassley (R-IA).

Grassley sent a letter to President Donald Trump calling out Price for his private travel expenses, and noting his predecessors’ use of commercial options where traveling within the lower 48 states.

The letter also demands that the Trump administration clarify for Grassley, who heads the Senate Judiciary Committee, “what steps the administration has taken to ensure that cabinet secretaries use the most fiscally responsible travel in accordance with the public trust they hold and the spirit and letter of all laws, regulations, and policies that apply.”

It’s a tough letter, which also dings EPA Administrator Scott Pruitt and Treasury Secretary Steve Mnuchin. You can read the whole letter here.

While fiscal conservatives can and should cheer the letter, even though it does ding figures some of us have regarded as champions, it’s also worth noting that Grassley may have extra reasons, beyond his sense of duty as a senator providing oversight of the administration and his own fiscal conservative credentials, for targeting Price and Pruitt especially.

Price, once regarded as a strong champion of lower drug prices (he was reportedly a quiet, but vigorous supporter of the 340B prescription drug discount program), has overseen the health care arm of an administration that has appeared to abandon various potential policies aimed at reining in drug prices and taking steps more in line with the policy agenda of PhRMA. PhRMA is the trade association representing pharmaceutical companies in Washington, D.C.

Grassley has emerged as something of a foe of pharmaceutical companies, and especially Mylan, whose settlement with the government over EpiPen prices Grassley harshly criticized. Buzz in D.C. is that Grassley may be unsatisfied with the Trump administration’s diminished focus on the prescription drug issue, as well as Price’s failure to get Obamacare repeal over the finish line.

Pruitt, for his part, is regarded as a major foe by many ethanol producers and ethanol advocates, while opponents of ethanol mandates tended to regard his stance on the issue of the renewable fuel standard and other pro-ethanol policies as a significant reason to install him at the EPA. Grassley is a champion of pro-ethanol policy, and a farmer (albeit of pigs).

Irrespective of what Grassley’s full rationale may be for going after administration officials for non-commercial travel, it’s clear that the spread of stories regarding pricey, taxpayer-funded travel is not playing out well for the Trump administration, and that congressional Republicans see it as a liability. Grassley appears committed to trying to separate the GOP, as a whole, from the administration on this, and that’s likely useful heading into next year’s mid-term elections.