Unlike nuclear weapons, a quantum computer is only dangerous if people don't know you have one. There are a number of ways of dealing with the security issues

Unlike nuclear weapons, a quantum computer is only dangerous if people don't know you have one. There are a number of ways of dealing with the security issues posed by quantum computers; most of them involve simply increasing the key length of your encryption keys. However, if people don't think you have a quantum computer, or you're able to make it better faster than expected, they won't change their behavior and so you have a fixed target.