I remember an Asimov short story in which scientists developed a machine that could see backward in time.
If I recall correctly, the upshot was the government became terrified because any machine that can see 1000 years into the past can also see 1000 milliseconds into the past and therefore functionally be used to spy on anyone in real time.
If I recall correctly, the upshot was the government became terrified because any machine that can see 1000 years into the past can also see 1000 milliseconds into the past and therefore functionally be used to spy on anyone in real time.