i reject the word "great", it is an opinion, not a description.
The US is powerful through its economy, military, technology and diplomacy - these help create a world that is easy for US to operate on its own terms.
Investors are leaving silicon valley. China is aligning new economies with itself.
If US loses control over different realms, it doesn't mean it will suddenly become weak. it means that US will need to work in a world that is more diverse than it is used to - something being powerful makes you very bad at doing.
Just because a country is powerful doesn't make it a desirable ("great") place for everybody to live in. Domestic quality of life is a mixture of public/private sector influence and culture. Americans have allowed money to drive their culture and business and politics.
Trump is a symptom of how this is working out. it's easy to blame everything on the biggest target. I'm not a politics person, but from what i understand, the problem isn't a specific party - it's mixing money and politics; it's the corruption of America's greatest quality - free speech.
