The government shutdown has had drastic effects across America. But there is no federal law mandating that it should be so severe. Instead, much of the shutdown’s impact is a direct consequence of a nonbinding legal opinion issued by Jimmy Carter’s attorney general, which could be easily be revoked by Eric Holder and the Obama administration. All they’d have to do is write a new opinion... and override 30 years of precedent.

Between 1974—when the modern era of budgeting started on Capitol Hill—and 1980, there were several government shutdowns. There was a period of 10 days during the Ford administration and then several shutdowns totaling 57 days during Carter’s term—but there were no catastrophic consequences. Affected employees weren’t paid and many programs suffered for lack of funding, but everyone kept on showing up for work and national parks and government offices stayed open for business. It was considered more of a “funding gap” than a full-scale shutdown.

This was perfectly acceptable. Just because Congress couldn’t agree on a budget or an appropriations bill didn’t mean that it wanted to shut down the government. Instead, it was a hiccup in the legislative process, not a catastrophe. That all changed in 1980, when President Carter asked his attorney general, Ben Civiletti, for a legal opinion on what the federal government could do during a shutdown. Civiletti’s position made all future shutdowns far more disruptive.

The underlying statute that keeps government from fully operating during a shutdown is an 1870 law, the Anti-Deficiency Act. The Constitution mandates that “No Money shall be drawn from the Treasury, but in Consequence of Appropriations made by Law.” But in the 19th century, the Executive Branch would enter into contracts without the consent of Congress. Congress would feel obligated to obey the contracts despite the lack of authorization. To prevent this from happening in the future, the Anti-Deficiency Act was passed to prevent federal employees from entering into any legal obligations that have not been explicitly authorized by Congress.

Civiletti strictly interpreted the Anti-Deficiency Act. As described in a report from the then-named Government Accounting Office, the only way to comply with Anti-Deficiency Act was “by suspending the agency’s operations until the enactment of an appropriation. In the absence of appropriations, exceptions would be allowed only when there is ‘some reasonable and articulable connection between the function to be performed and the safety of human life or the protection of property’” as well as when activities are explicitly funded one-year appropriations or authorized by other legislation.

This interpretation has guided all government shutdowns since, including the 21-day closure during 1995 and 1996. But it doesn’t have to do so.

Charles Tiefer, a professor at the University of Baltimore School of Law and perhaps the country’s leading expert on the Anti-Deficiency Act, says that while “it’s not a cinch to overrule the Civiletti opinion at this moment... I do think that we’re not bound by the Civiletti opinion once we go past 21 days.” Tiefer believes that once the 21-day mark is reached, there’s no precedent to keep the government shut down; especially “as long-term problems accumulate because we’re in new territory.” This means that once the shutdown has gone on for 21 days, Civiletti doesn’t apply and the Obama administration is free to ignore it without formally overruling it.

Tiefer emphasizes his view by noting that most of the focus in the Civiletti opinion, as well as government planning for a shutdown, is what happens on the day of a shutdown. All of these plans focus on a short-term interruption in services, not a major impasse like today’s. Thus, this shutdown could be distinguished from past occasions where the government was shuttered and Civiletti put to the side.

Admittedly, there would be some legal challenges to overturning more than 30 years of precedent, or at least distinguishing this shutdown from those in the past; but it would be hard for a justiciable case to reach court. After all, plaintiffs would have to show actual harm done to them by a government functioning without a budget and would have to do so while the government was still closed—otherwise the case would likely end up being ruled moot. Instead, the challenges would be political. There would be indignant House Judiciary Committee hearings and angry talk of impeachment among some Republicans.

There is no silver bullet to end the shutdown. Congress has to pass a continuing resolution. But, it’s entirely possible that, with one simple legal opinion, the White House can at least mitigate many of the worst effects of the shutdown.