As the oldest democracy in the world, with a deliberate 2 party system that is essentially ideologically similar, the US political system is quite resilient. Yes, a "deep state" or a "military-industrial complex" does have enormous influence over the country - but there's nothing truly insidious about it when you realise that it is a part of the US political system. It is somewhat undemocratic, but it still acts as one of the checks and balances of US political system to ensure the US remains a superpower (i.e. it only comes into picture on superpower politics). It is composed of the core of the US capitalistic system, whose leaders also have a lot of political influence. Both the US political parties understand that you need this "deep state / MIL complex" to continue to be a superpower, and so a US President is only ever allowed to freely exercise his democratic powers domestically (i.e. in America) and for routine foreign diplomacy. For anything else related to superpower politics, the President of the US does not have a free hand in any manner of speaking - it's a 100+ year old idea and institute that has ensured the US becomes the eminent (and now sole) superpower in the world.
And Trump is going to be a President only for a few years. (Again, note, by design - term limits in the US political systems ensure authoritarianism cannot flourish).
Moreover, many might not remember that once the US developed nuclear weapons during WW 2, with the help of British and other European scientists, it immediately expelled British scientists from its research labs and worked to deny this technology to the British. The British had to do their own research to create nuclear weapons. (But they still chose to be dependent on the US because they understand the value of alliances - it's always better to fight a war alongside someone, than alone). The delivery systems for nuclear weapons are much easier to create, especially when you have wealth and help from others (alliances). Even if by some rare and extraordinary fluke, the US explodes from within, the British can easily catchup.