Answer:
Judicial review is a distinctive power of the Supreme Court not mentioned in the Constitution.
In the beginning of this country, and for quite awhile, no one was really sure what the Supreme Court's function really was. In the Marbury v. Madison case (Feb., 1803), Chief Justice John Marshall asserted the main principal on which Judicial Review rests, noting: 'it is emphatically the province and duty of the of the judicial department to say what the law is".
Judicial review is how the court determines the meaning of the Constitution. If you believe that Supreme Court Justices appointed for a lifetime tenure by whatever President happens to be in office at the the time a new Justice or two or several must be appointed, then it's democratic, especially if you share the ideology of the appointees and their nominating President. If you don't share their vision and beliefs, then it isn't.