Is the united stated a true democracy?

No. The United States is a republic. A democratic republic, but a republic. A democracy is simply 'majority rules'. Our system is more complex. Our President may sign an executive order, but that could be overruled by Congress. A simple majority prevails in the House of Representatives, but not the Senate. Even our Electoral College system of voting in a new President is not simply made by popular vote or 'majority rules'.