Patriot Act Revisited

If the Patriot Act allows the government to tap phone lines without a warrant then what prevents them from keeping tabs on random people and their habits or from spying on private meetings much like the Watergate scandal? For example the government could keep tabs on waiters and how much tip money was made compared to how much was claimed for taxes by recording phone conversations near or after closing time for restaurants. While it is illegal not to claim all your money it is not necessary for the government to get that intrusive. Another example might be if you have a friend who happens to be Muslim and you are discussing fundamentalist Islamic beliefs you may be classified as a potential terrorist making it difficult to go through security at airports. Also, what prevents the government from spying on opposing candidates in an upcoming election? They could find out everything the candidate was going to say or discuss, which would give the President or government official an obvious advantage. Good bye Watergate, hello SS and KGB. All of this is made possible by the Patriot Act and I find it disturbing. Nixon resigned as president for spying; Bush made it legal to spy and for some reason the public seems to love him for it? Go figure. I need to move to France (I would say Sweden but it is cold up there).