The longest and most absurd government shutdown in US history came to a temporary end last Friday. But it could not have dragged on for five weeks if its impact had not been blunted by 400,000 federal workers’ being compelled to stay on the job without pay. And that was only possible because the United States has some of the weakest labor protections in the developed world.

Pissed-off federal workers played a big role in ending this impasse, but they didn’t end the 16-day shutdown that Senator Ted Cruz launched in a futile attempt to get Obama to delay the Affordable Care Act in 2013, and they didn’t end the 21-day stoppage that Newt Gingrich used to pressure Bill Clinton to cut spending in late 1995 (if you’re sensing a theme here, there’s good reason). The reasons it took an extraordinarily long shutdown, with no end in sight, before federal workers had had enough is straightforward: They’re barred by law from striking—or organizing wildcat actions like “sick-outs.” And most care about the work they’re doing and don’t think risking a job and a pension and health insurance over a short-term political tussle in Congress is worth it.

This latest budget saga did give way to a new political truism: Protracted lockouts of federal employees will end two hours after enough air-traffic controllers–or TSA agents–stay home, grinding air traffic to a halt. But that’s really a simplification. On the 30th day of Donald Trump’s second shutdown in as many years, Sara Nelson, president of the flight attendants’ union, gave a fiery speech calling on members of the AFL-CIO to talk to their local chapters “about all workers joining together to end this shutdown with a general strike!” Four days later, a Democratic proposal to end the lockout with no money for Trump’s border wall got more votes in the Republican-led Senate than a GOP alternative with funding for a wall, and, with his party becoming increasingly skittish, Trump reportedly decided he needed to end it. The day after that, federal workers missed their second pay period, a handful of air-traffic controllers called in sick, travelers got tangled up, and Trump relented.

In much of the highly developed world, locking out hundreds of thousands of public servants and compelling hundreds of thousands more to work without pay would lead to strikes, because working people, including public-sector employees, enjoy far stronger protections for strikes. In several countries, the right to strike is grounded in core civil liberties—the freedom of speech and assembly. That’s not the case in the United States, where the courts have not interpreted the First Amendment to guarantee a right to strike. Extended lockouts would be impossible if they did.

Cynthia Estlund, an expert in labor law at New York University’s School of Law, says that in countries with a presumptive right to strike, public officials would have to justify any law against public workers’ striking. They would have to “draw lines between essential and non-essential personnel based on whether they actually provide critical services—things like fire safety.” If federal workers weren’t truly necessary to keep people safe, they couldn’t arbitrarily be deemed “essential workers.” Estlund noted that in Canada, “which has much of the same legal architecture that we do but recognizes a constitutional freedom of association and right to strike,” there might even be a process “to decide how many workers you need in some essential category. They would try to respect the right to strike and would look at what exceptions are justifiable rather than it being a matter of executive discretion.”

If Americans enjoyed that right, federal workers who don’t have life-or-death jobs would enjoy the ability to go on strike. But, more relevant to shutdowns, Trump would not be able to compel federal workers whose jobs make the shutdown less painful for the public to keep working jobs that aren’t truly essential. And that is precisely what happened during this latest record-shattering shutdown.

Before Trump caved last Friday, I spoke to a furloughed federal worker named Scott, who asked that The Nation not use his full name because of the “vindictive” nature of the Trump White House. This situation did not sit well with him. “One of the biggest frustrations is that we have the ability to bring so many federal employees into work during a shutdown that American citizens don’t even feel the effects,” he told me. “‘Essential employees’ are supposed to be those who are necessary to maintain the safety of this country, but it’s gotten to the point where anybody who would interact with the public, or make sure the public doesn’t feel the full effects of this is called ‘essential.’”

Scott pointed to the Food and Drug Administration’s decision to recall food inspectors during the third week of the shutdown, following news reports that food safety was being put at risk. Those food inspectors were among “tens of thousands of federal workers” the Trump regime brought back to work that week “to fulfill key government tasks, including disbursing tax refunds [and] overseeing flight safety,” according to The Washington Post. Bloomberg reported that the administration had designated the people who process permits to drill for oil offshore as “essential” workers while “programs that are out of favor with the White House—such as the Energy Star consumer ratings system—aren’t getting the same treatment.” During the last lengthy shutdown in 2013, conservatives had accused Obama of arbitrarily closing national parks in order to pressure Republicans to negotiate; this time, they remained open to the public, but with only “skeleton staffs,” and were totally trashed by the time Trump reopened the government.

In one sense, the politics of brinksmanship which has become central to Republicans’ governing strategy is possible only because of the right’s long war on organized labor. One of the first efforts to organize public workers was the Boston police strike of 1919. According to Erik Loomis, a labor historian at the University of Rhode Island, Calvin Coolidge, then mayor of Boston, crushed that strike by firing all of the striking cops. Coolidge parlayed that assault into national prominence, and ultimately the presidency. “That really put a damper on public-sector organizing,” said Loomis. There would be little in the way of public-sector organizing until the late 1950s. Then, in 1970, the postal workers went on strike demanding better pay and the right to bargain collectively. It would be the biggest wildcat labor action in US history. “That was a groundbreaking strike,” Loomis told me. “It put the Nixon administration on its heels. They didn’t really know how to deal with it.” The postal workers ultimately saw most of their demands met.

There were other wins and losses throughout the 1970s, when the public-sector unionization rate was at its peak and four in 10 workers belonged to a union. And then in 1981, the Professional Air Traffic Controllers Organization went on strike and Ronald Reagan fired them, killing the union and effectively ending that brief period of public-sector radicalism kicked off by the postal workers a decade earlier. According to Cynthia Estlund, that action still reverberates today. “[The air traffic controllers] thought, ‘We’ve got clout, they need us. We know it’s illegal to strike but we think we can get away with it.’ And Reagan pulled the trigger—he declared the strike illegal and summarily fired them all. It caused some serious, temporary disruptions in air travel, but it really sent a message that is still being heard by especially unionized federal workers.” Of the calculus today’s public-sector workers must make, she added: “Maybe it would go down differently this time, but of all the people you might think would be willing to pull the trigger, Trump is right up there.”

After the shutdown ended, some on the left called on organized labor to “walk out” as soon as the next one begins. But Scott, who’s worked for the federal government for 10 years, has a different view. “I understand that inclination, but it’s really an unfair burden—it’s not fair to put the onus on federal employees to do that.” He added that “this is not an administration that’s friendly to federal workers. If the federal workforce were to be gutted by say 15 percent, they wouldn’t have an issue with that, and they wouldn’t be looking to fill those positions. As federal employees, we’re aware of that—I wouldn’t risk my job because I know I wouldn’t be replaced, and I think my job’s important and want the work to continue.”