As a voting member of the U.S. electorate, I agree with much of what you say. We are certainly at a crossroads. This election may be the end of democracy, as we have known it (no matter how imperfect it has been). That statement, end of democracy, is not hyperbole. Trump (who seems to be destined to win because an old man won't move over--I'm old, I can say that) has promised many times an end to democracy. He has promised to upend the Constitution. He has promised to become a dictator on Day #1. He has promised that with the engine of government he will prosecute his personal agenda, whether that be vindication or avarice. Somehow, the people who are voting for him don't hear this. Or, maybe they are weary of democracy. Maybe the tumble of it all, the free fall into electoral disorder every four years seems dangerous to them. I don't know. I've learned not to try and put myself in the minds of others.
However....Don't take the assassination attempt too seriously. It's in our blood. We have been assassinating, or attempting to assassinate, our presidents throughout our history. The first successful attempt was Abraham Lincoln in 1865, but someone tried to kill Andrew Jackson in 1835 before that. We're a gun culture. That's how we settle differences, with a gun.
Also, as for the divisions in the country. Nothing new there. We were crudely knitted together by compromise at the very start. You had northerners and southerners, country folk and city folk, small states and large states, farmers and businessmen. There were serious rebellions from the very start (Ex: Whiskey Rebellion). We have never been a unified country. We fought a civil war because of the differences. Every election there are red states and blue states, with people that have radically different views of government.
What's different this time is that so many people are willing to give up on democracy. So many people think it is a tired idea. So many people are willing to give up the rights others died for. That's what is unique about our time.
In 1787 Benjamin Franklin was asked, at the writing of our Constitution, whether the government formed was a republic or a monarchy. His answer, "A republic, if you care to keep it".
It seems that many people in this country--Trump voters--do not care to keep it.
It’s like the US is being hold together by the dollar and the desire to be world dominant
Of course I'm looking at it up close, and that may distort my perspective, but I think it's something else that holds us together--and tears us apart. Almost more than any other nation, the United States is held together by an idea. The nation was formed by an idea. We just don't agree on how to be loyal to that idea. Everybody waves a flag. Everybody is patriotic, but we all mean something different by patriotism. We haven't been around long enough to have a racial, or even ethnic identity. We share an ideal, but we can't agree on what that ideal is. So we fight over whether religion or agnosticism is part of the idea. Whether equality of opportunity, or untrammeled ambition are essential to the idea. We all want freedom here, but can't agree on what freedom is. We are more than our money, or our will to dominate--although making money is essential to our national ethos, and dominating (Manifest Destiny, for example, and Dollar Diplomacy) have been an important part of our history. We are driven by an idea of what it means to be an "American". This is Donald Trump's emotional appeal. He claims to represent true Americans. He claims to be taking "America" back. Back from whom? From those who don't agree with his ideas.