Yes, the U.S. is in danger of losing its democracy. Given the next four years of the Trump presidency and the most recent stripping of rights from American citizens, the U.S. democracy, as we know it, is crumbling. Based on President Trump's plan of action, it doesn't seem that he has an interest in the government that was once, "For the people, by the people."
Donald Trump's administration is a catalyst for the U.S. losing it's democracy. There have already been signs that freedom of speech and the press are under attack; bans on entire religions and races are being considered. These are early signs of a democracy in shambles. Fear has led us to this and the spin doctors who formulated it.
We became a democratic republic afterwards from the demands of those who where always considered the common rabble. Now we are returning back to what seems to be the natural state of any large human society, some form of exploitative oligarchy.
Democracy (or a democratic republic in our case), just like a large and strong middle class, is an artificial entity created by the work of the common man; and just like any other artificial structure it will be eroded and destroyed over time without maintenance which the people are to divided and disinterested to do.
I think the overall semblance of democracy is still here and always will be here. There are some deep-rooted constitutional mandates that need to be overhauled for the US to become a democracy worthy of the 21st century. I doubt whether that is going to happen. There's no time for the education system to change so the population's sentiments will remain the same in the future. This in turn will keep the current political climate the same for years to come.
For heaven sakes - The United States is not in any danger of losing its democracy. In the first place, America was founded as a democratic republic - not a full blown democracy. Nonetheless, voters still vote for the president, Congress, governors, state legislatures, etc. America will continue to be ruled by elected officials.