Rawls' "justice as fairness" attempts to have people look through a lens where they do not consider their own interests, only what is fair. Rawls theory is extremely important because it attempted to bring fairness to an unfair society. Essentially, you are supposed to forget who you are when you make decisions and think what is the most fair thing to do for society. Rawls believed the biggest crime is to make a decision or action that could limit someone else's "rights and freedoms."
I believe Rawls' theory is very considerate, which I appreciate, but I do not believe it is an attractive guide for running a state. It is certainly important to understand one's biases, advantages and how others do not have those same privileges, however those factors are still involved in one's decision making. Rawls' theory is also a bit antiquated (created in 1971) and since many social scientists have found criticisms with his theory. I believe the most important criticism is that "The theory was developed more to handle problems within society and there are difficulties in applying the principles to individual decision-making involving specific others." (Queensborough Community College)
Ultimately, this is an important theory for political leaders and judges who can more easily consider the whole rather than individuals who have very different and specific problems.