Tuesday will mark one month in the shutdown of the U.S. government, with no end in sight. Federal workers are lining up for food in Washington. More than 400,000 government employees have worked that entire time without pay, few of them more visible than the screeners of the Transportation Security Administration.

Last Monday, I wrote that if any group of government employees could end the shutdown, it would be the 44,000 TSA screeners who keep the nation’s airports running. The next day, Washington Post reporter Robert Costa wrote that GOP lawmakers see a TSA walkout as Trump’s Achilles’ heel—the one factor that could force the president to back down from his demand that lawmakers fund a border wall.

Couple senior Republican lawmakers tell me the only way this breaks open is if TSA employees stay home and Americans get furious about their flights. That’s the only out, they say. And they’re close to the WH. — Robert Costa (@costareports) January 15, 2019

On Friday morning, backed by members of the United Steel Workers, the Teamsters, and other private-sector unions, one chapter of the union that includes the screeners—Local 332 of the American Federation of Government Employees—held a rally at Pittsburgh International Airport to raise awareness about the workers’ declining morale and dire financial position. “There are real people out here, fighting for their lives, fighting for their homes, fighting to feed their kids,” TSA officer Ava Basalyga said, according to the Pittsburgh Tribune-Review.

It’s illegal for the TSA to strike, as Barbara Ehrenreich and Gary Stevenson called on them to do in the New York Times this week. Instead, the union that reps the TSA, the American Federation of Government Employees, has sued the federal government. One in 15 TSA workers called out on Thursday—about double the normal rate, but well short of an absence that would cripple commercial air traffic.

What if TSA workers did walk out? There’s a worrisome precedent: the 1981 air traffic controllers walkout. Like the TSA screeners, the controllers were forbidden to strike. Like the TSA screeners, they were upset with their pay. Like the TSA screeners, they thought their role gave them leverage over Washington.

President Ronald Reagan ordered them back to work within 48 hours. On Aug. 5, he fired the 11,500 controllers who had not returned to their jobs and banned them from federal employment for life. Airline travel was disrupted for weeks, but there were no accidents. The union was dismantled. Many of the controllers never recovered. It was a defining moment for Reagan and cowed the American labor movement for decades to come.

In the American Prospect, Joseph McCartin, a historian and the author of Collision Course: Ronald Reagan, the Air Traffic Controllers, and the Strike That Changed America, makes the argument that it’s time for the TSA to get sick—a reliable onetime pressure move for federal workers that Reagan’s dismissal of the controllers union, the Professional Air Traffic Controllers’ Organization, all but put an end to. On Thursday, I spoke to McCartin about four reasons this time is different—and why federal workers should escape the long shadow of 1981.

Public opinion

Air traffic controllers were making higher-than-average salaries in 1981, and they struck for a $5,000 raise—no small thing. “They were seen as well-paid workers already,” McCartin said. All this was happening as the nation recovered from the small 1980 economic downturn and slid into the worst recession since the Great Depression. “The public was primed to side with Reagan.” TSA screeners, by contrast, start off making just $15 an hour; the median screener makes $40,000, according to the Bureau of Labor Statistics—about 20 percent less than the average American salary. Oh, and of course, they’ve been working for a month for nothing during the longest run of private-sector job growth since World War II.

Furthermore, Reagan had recently won 44 states, and his popularity was soaring; Donald Trump has shut down the government over a wall, and his popularity is falling.

Preparation

It was clear as early as 1979 that there was a risk of a strike when the PATCO contract ran out; Reagan called the possibility a “peril to national safety” during the campaign. Just as police unions today use “slowdowns” to circumvent strike bans and show their discontent with public officials, PATCO had previously used unauthorized “sickouts” to have its demands met.

“I asked many of them, ‘What did you think when Reagan said you have 48 hours to return to your jobs?’ They said they thought he was crazy,” McCartin recalled. “They felt, Reagan can threaten all he wants, but they can’t run planes without us. What they didn’t reckon with was the degree to which the administration had prepared for all this.” The administration had military flight controllers ready to step in and moved quickly to train replacement controllers, sometimes fudging test results to get them on the job quickly. The gamble paid off: After a period of disruption, air travel resumed sans PATCO.

Needless to say, it’s difficult to imagine the Trump administration has such a plan in place or could execute one if they did. (Federal Aviation Administration employees including controllers have also been working without pay since December, so they might not be gung-ho about breaking a TSA sickout to keep the government shut down.) Finally, it’s not clear there is an equivalent workforce trained and ready to replace TSA scanners at a moment’s notice.

The airlines

Air travel was a mess in 1981. Barely two years had passed since President Jimmy Carter deregulated the industry, and many carriers were still in a defensive posture, flying half-empty planes on newly competitive routes. FAA chief Lynn Helms got the airline brass together that summer to prepare for the disruptions of a PATCO strike and urged them to see it as an opportunity, McCartin said. They agreed.

“[PATCO] thought the airlines would bang on the door of the White House and say, ‘Get the controllers back to work, we’re bleeding to death!’ ” McCartin observed. “But they used it as an opportunity to get on the hub-and-spoke model we’re familiar with. There was massive disruption, only tolerated because the airlines took advantage of it.”

Again, it is hard to imagine the Trump administration working with airline CEOs to prepare for a sickout—and harder still to imagine today’s carriers gamely tolerating days or weeks of disruptions.

Air traffic

There are tens of thousands more TSA workers now than there were air traffic controllers in 1981. Covering for them would require an enormous deployment of manpower. Air travel is much more central to the U.S. economy now than it was then. U.S. airlines carried 849 million domestic passengers in 2017, up from 297 million in 1980.

All this activity is tightly scheduled and interconnected. A sickout doesn’t need to be national, McCartin noted, to cause a national disruption. It just needs to hit a few key hubs, like Atlanta, Chicago, or New York.