As recently as Thursday evening, elected officials were engaged in theatrical, go-nowhere resolutions with no real chance of reopening the government.

But by Friday afternoon, President Trump abruptly announced a deal to reopen the government, at least temporarily. What changed in less than twenty-four hours? Massively disruptive worker sickouts and the threat of strikes.

Earlier this week, Association of Flight Attendants (AFA) international president Sara Nelson raised the possibility of a general strike to fight the shutdown, and a group of aviation unions issued a dire warning that the aviation system’s safety was degrading.

Then on Friday, the second missed payday of the shutdown, a significant number of air traffic controllers called out from work, temporarily grounding all flights at New York’s LaGuardia airport and causing flight delays across the East Coast. A source inside the White House told CNN Friday that the flight delays were a “contributing catalyst” to the hasty deal.

As news of the delays spread, Nelson immediately raised the possibility that her union members might engage in a “suspension of service” due to safety concerns in an interview. She also told New York, “We’re mobilizing immediately …. If air traffic controllers can’t do their jobs, we can’t do ours.” She carefully avoided claiming the union was preparing to organize a strike, but the implication that there was a very real possibility of a work stoppage was clear.

Because of federal workers’ severe lack of labor rights and the fraught history of labor relations between air traffic controllers and the government in particular, we may never know the extent to which the call-outs were organized or how big they were. But given that they came on the symbolic date of federal workers’ second missed payday and followed a week of increasingly dramatic rhetoric from aviation-sector workers, some degree of worker coordination both within and across unions seems reasonable to assume.

And there is no other explanation for Trump and the Republicans’ quick reversal besides workers’ threat of disruption. They were comfortable introducing a bill with funding for a border wall — which they knew would not pass — on Thursday. But mere hours after workers threatened to disrupt the country’s aviation system, the Right immediately reopened the government. In fact, such action is exactly what the Right itself predicted it would take to end the shutdown.

Many federal workers will understandably want to simply return to work and put the lockout behind them. But the shutdown and the way it ended show that it is critical for federal workers to keep organizing.

The fact that the lockout was able to go on so long without an effective response will embolden the Republicans to use the tactic again. In fact, Trump’s proposal only funds the government through February 15, at which point the whole thing could start over if no permanent agreement is reached. And while legislation to provide back pay to government subcontractors — many of whom are low-wage workers — has been proposed, the deal as it stands does not provide for them.

But the speed with which Trump folded when faced with a serious disruption to business as usual at workers’ initiative shows how much power federal workers have — if they come together and figure out how to use it.