As far as designing in weaknesses and/or golded keys. Well, it does not add to security, but assuming that the other nation states are already able to break encryption and read what they want, it does not weaken it either for national security reasons.
That assumption is the weakness in your argument. If you design in a systemic back door, it becomes a known fact that a hostile actor could find a way into your system, because you have created one for them. Not only that, but in the case of a golden key, if it leaks then anyone can get in.
Of course there is no guarantee that any encryption scheme is 100% unbreakable. Such is the nature of mathematics and research. But there is a fundamental difference between needing to discover a systemic weakness in an encryption scheme, say an efficient solution to the discrete logarithm problem or a side channel attack on a given implementation, and merely needing to know some master password that will work even if the mathematics of the encryption method and its practical implementation are sound.
That assumption is the weakness in your argument. If you design in a systemic back door, it becomes a known fact that a hostile actor could find a way into your system, because you have created one for them. Not only that, but in the case of a golden key, if it leaks then anyone can get in.
Of course there is no guarantee that any encryption scheme is 100% unbreakable. Such is the nature of mathematics and research. But there is a fundamental difference between needing to discover a systemic weakness in an encryption scheme, say an efficient solution to the discrete logarithm problem or a side channel attack on a given implementation, and merely needing to know some master password that will work even if the mathematics of the encryption method and its practical implementation are sound.