Civilization self destruction prevention

In 1950 physicist Enrico Fermi wondered why we have found no alien civilizations even though there are about 10,000,000,000,000,000,000,000 stars in the observable universe.

Among other things, he worked on nuclear power.

Nuclear weapons helped nations prevent wars. And, luckily, your socially challenged neighbour that every now and then threatens to kill someone with his automatic rifle, couldn't enrich uranium even if he wanted to. Everyone could sleep safe, knowing that they won't wake up to a bright flash of light that will kill 10,000,000 people instantly.

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Year 2060.

3D printers have evolved to the point they cost as much as normal printers did in 2015. They can "print" extremely complex objects in very small amount of time, be it food, or a complex machine.

Drones sized a few micrometers are used routinely to cure previously incurable diseases.

Life expectancy has skyrocketed to 150 years.

What a great time to be alive!

Or is it? Your neighbour no longer has a rifle. He has a 3D printer which he used on creating uranium enrichment devices. He also printed a fully functional nuclear weapon. The final piece of the puzzle is that fist sized ball of U-235. He has been working for half a year on his project. Soon the whole world will know him and fear him! They will finally respect him!

As he sits in his room waiting impatiently, he feels an insect on the back of his neck. 5 seconds later, he drops on the floor. His heart stops as the toxin injected by the fruit-fly-sized drones reached his neurons.

Police neutralized the suspect.

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The problem is that you have 10 billion "neighbours". If 1 in 10,000 wants to destroy society, that's 1 million crazy neighbours.

• How hard would it be to protect our civilization from total annihilation?
• Which measures would governments have to take in order to achieve that? Would personal data cease to exist as we know it? Would everyone be under surveillance?
• Is it even possible to prevent self-destruction indefinitely?