The Environmental Protection Agency’s independent watchdog can’t keep up with all of Administrator Scott Pruitt’s scandals. In January, EPA Inspector General Arthur Elkins revealed that his office will limit its investigation of Pruitt’s controversial first-class travel to the previous calendar year. The Office of the Inspector General lacks the “people, time and funds” necessary to investigate the matter beyond 2017 while continuing its other investigations, Elkins wrote in a letter to House Democrats. “The fact is that the OIG has been funded at less than the levels we deem adequate to do all of the work that should be done, and we therefore have to make difficult decisions about whether to accept any given potential undertaking.”

That the OIG must cut short any investigation due to insufficient resources is troubling enough, but even more so given the revelations about Pruitt’s travel in a Washington Post report this month. The Post found that in June alone, Pruitt and his entourage racked up at least $90,000 in travel bills, mostly from exorbitantly-priced first-class flights and one $36,000 military jet from Cincinnati to New York. Under pressure to justify these costs, the EPA said Pruitt has a “blanket waiver” to fly first class wherever he goes, due to vague “security threats.”

How is it that EPA can afford such luxurious travel, but not enough money for its independent watchdog to investigate whether that travel was improper? The EPA and its OIG have separate budgets—and Trump wants to further tighten the OIG’s budget. If he gets his way, this wouldn’t only limit scrutiny of Pruitt, but of the programs that reflect the EPA’s core mission of protecting Americans from pollution.

Pruitt is the subject of at least four OIG investigations opened last year at the request of Democrats in Congress, including the travel audit (which was expanded twice). The OIG is looking into Pruitt’s four-day, $40,000 trip to Morocco to promote the use of American natural gas, which may be improper because the EPA has no role in natural gas exports; his purchase of a $25,000 soundproof security booth for his office, which may have run afoul of appropriations law; and his use of EPA enforcement agents to provide him with 24/7 security detail, which may be improperly pulling resources away from enforcement programs against polluters.

An OIG spokesperson declined to detail the cost of these investigations, citing their ongoing nature. The travel audit appears to be the most demanding. OIG investigators will have to obtain and audit of hundreds of receipts for Pruitt, his many aides, and his security detail. Staff must then determine whether EPA travel policies were followed for each individual on every trip. That’s a lot of work, said Peter Tyler, an investigator for the Project on Government Oversight. “This looks like a full-on audit to be written by the IG himself,” said Tyler, who used to work in the inspector general’s office of the Department of Health and Human Services. “It seems legitimate for them to say, I’m setting a priority, and only looking at 2017.”

Inspectors general across the government—there are more than 70—consistently struggle to prioritize what to investigate with their limited funding. It’s a problem that dates back decades, as Laura Reston reported for The New Republic last year. “[Inspectors general] serve as the frontline against government waste and fraud,” she wrote. “Studies show that for every dollar invested in their offices, they save taxpayers $14.” Still, many inspector general positions across the government remain unfilled, while budgets in others suffer. The budget for the EPA’s relatively small OIG office, which has 253 employees, has hovered around $41 million since at least 2014. Trump’s recently released budget proposal would reduce it to $37.4 million.

Limited budgets often force inspectors general to choose between investigating an agency’s spending or evaluating the effectiveness of its programs. The EPA’s mission, for instance, is to protect human health from pollutants. “The EPA is dealing with life and death issues,” Tyler said. “Are kids still dying of lead poisoning even with EPA lead programs? That’s a question OIG could answer.” The agency’s OIG does investigate some programs intended to improve human health, but it’s also required by Congress to publish numerous yearly reports. The office, for example, must audit and assess EPA employees’ financial statements and credit cards and their compliance with cybersecurity and data preservation laws.

Surely the OIG, despite its limited budget, could evaluate more EPA programs if it weren’t conducting so many investigations into Pruitt—and on behalf of him. The office routinely investigates security threats against him, which are unusually numerous for an EPA administrator. Those investigations, however, don’t appear to have found much so far: In July, the OIG found that two female protesters who were deemed a “security threat” by Pruitt’s security team after briefly interrupting a speech could only be charged with a misdemeanor for unlawful entry to a private event, and the U.S. Attorney’s office declined to prosecute. Another OIG investigation into a “threatening tweet” also resulted in no charges after the woman apologized. (She said she’d gotten overly angry while drinking and watching The Rachel Maddow Show.)

Ironically, these same “security threats” are the ones Pruitt uses as justification for his expensive first-class travel habit. “Unfortunately, ... we’ve had some incidents on travel dating back to when I first started serving in the March-April timeframe,” he said earlier this month. The Associated Press later reported that “unpleasant interactions with other travelers” led to the blanket waiver. But the OIG only has to look at its own files to figure out if that justification is warranted: None of their investigations of threats to Pruitt pertained to air travel, a spokesperson recently told Politico.

Ideally, the EPA’s OIG could focus on making sure agency programs are efficient and effective. But doing both with so little funding is challenging, and the current administration is making it even harder. Pruitt’s personal scandals aside, Trump is aggressively repealing anti-pollution regulations, so it’s more important than ever that the OIG evaluate whether the EPA is fulfilling its core mission. It’s a shame that the OIG has to choose between investigating administrative waste or programs to protect public health; few would fault the office for prioritizing the latter. But it’s a false choice, because any well-functioning government operating in good faith would provide its watchdogs with enough funding to do both.