The structure of the US makes it basically the single most secure democracy anywhere right now or in history. No country in Europe or Europe as a whole is even competitive by comparison. The main issue we're facing is that we are by far the primary target for foreign funded activism and systemic attacks, because China and Russia hated NGOs promoting color revolutions.
That is also part of the rule of law issue, but the system is overall managing quite well. It's all moving in slow motion, but many important metrics are going in the right direction, which we need as that's part of deterring China.
"The United States was the most prominent liberal democracy for much of the 20th and early 21st centuries, but has undergone significant democratic backsliding and a shift toward a hybrid regime—a political system combining autocratic and democratic features.[185][186][237] There is an ongoing debate among political scientists on whether the country is more appropriately classified as an electoral autocracy or illiberal democracy, with few still considering it a robust liberal democracy.[238]"
How do you figure? I hear you have roving gangs of masked thugs beating up random citizens with the backing of your government, that doesn't sound very democratically secure, especially with what healthcare costs over there.
This is just not true. It is failing visibly and loudly fast. It used to fail slowly but the process speeded up.
American administration supports Russia now. It praises Russian, Chinese, Belarus leaders again and again. It praises Orban. It hates last bastion of democracy - Europe.
China is not detered. Its power is growing while American one is going down. Trump openly admires its leader. China is celebrating current state of America.
So secure, in fact, that it has secured itself even against the influence of its own citizens.
Also, we have guns. LOTS of guns. The U.S. military's first and sole responsibility is to the constitution itself. If any state or the federal government tries to get rid of their constitutions, the military can rightfully take it over and re-establish a constitution.
There is no other country that's even remotely close to this secure.