The verse below explains how they do it as all we do is sit back and complain:
Because sentence against an evil work is not executed speedily, therefore the heart of the sons of men is fully set in them to do evil.
---ECCLESIASTES 8.11
More on insider trading at these LINKS:
http://thenewsunit.blogspot.com/2011/11/us-congress-and-legalized-lawlessness.html
http://thenewsunit.blogspot.com/2011/06/senators-and-congressmen-exempt-from.html
http://thenewsunit.blogspot.com/2011/09/is-obama-insider-trading.html
http://thenewsunit.blogspot.com/2011/11/congressional-insider-trading.html
...developing...