In 1948, the Supreme Court ruled that Hollywood's five biggest studios had been running an illegal monopoly. People remember the case as the government ordering the studios to sell their theaters. That's not what happened. The Court banned the worst practices, sent the theater question back to a lower court for a fresh look, and left the door open.

Howard Hughes walked through it in the wrong direction. He volunteered to split RKO's studio from its theaters before the lower court even ruled. Every other studio watched him do it and followed.

The system that had controlled American moviemaking since the 1920s collapsed in under a decade. What grew in its place changed everything.

This week we hit Control Z on Hughes's signature, and follow what happens when the first domino refuses to fall.

On October 20th, 1980, Ronald Reagan wrote the president of the air traffic controllers' union a letter calling their working conditions "deplorable" and promising his administration would fix them. PATCO endorsed him three days later. It was the first time the union had ever backed a Republican.

Ten months into his presidency, 11,400 controllers walked off the job. Reagan gave them forty-eight hours to come back. When the deadline passed, he fired every single one of them, broke the union, and dared the FAA to keep the planes flying with less than a third of its workforce.

The planes kept flying. The consequences took longer to arrive.

This week we hit Control Z on the forty-eight-hour deadline, and follow what happens when the president who promised to fix the system decides not to destroy it.

On a computer, Control Z is the undo button. When you press it, whatever you just typed gets reversed and allows you to make a different decision.

What if you could press control Z on some of the biggest decisions in history?