If you are 40 something and the president's plan goes through, you will have 20 years (assuming that you want to work to 65) to also put 4cents of every dollar you earn into a private account instead of the govt general revenue. That is a lot of money that congress will never have under their control. You will. You will not see a lower net income when you retire, than you would if the status quo remains the law.
That's not what president Bush himself has communicated. I'm 46 years old.... born in 1959.