>>3Onion routing was originally a whitepaper created by the government to secure government communications so that they could send people to foreign countries and still communicate back and forth securely.
The Tor Project decided to actually make the software and released it in 2002, and while there are a number of plausible ways to possibly circumvent how it works, none have really been proven to work, and as long as there are more and more random people adding nodes and using it, it should continue to be safe.
And yes, the Government does use Tor too, so hopefully they realize if *they* find a vulnerability, that means someone else can find the same one, and that will lead them to help fix it.