Critical Race Theory argues that laws and legal reasoning are not value-free and are affected by the political and economic climate in which they are created.  Laws encode the values of the dominant group, and the resulting social/legal structure maintains these values.  Furthermore, the interpretation and implementation of laws are largely done by the dominant group and thus maintain its power. 

The civil rights movement had much success in striking down overtly discriminatory laws.  However, gains in desegregation, housing access, fair employment, and university admissions were gradually undone by a conservative shift in the Supreme Court and push back by conservative politicians.  Critical Race Theory developed out of a frustration with the progress of change and the persistence of racism.  Changes in the law did not lead to equitable outcomes.  CRT used a racial lens to highlight the systemic racism of our institutions and society.  For example, the court decided that to prove discrimination a plaintiff needed to show that there was discriminatory intent rather than an unequal effect.  So, if a school district became segregated because white students moved to the suburbs or to private schools, this unequal effect could not be remedied unless the school administrators were judged to have intended this segregation effect. 

This shift in focus from effect to intent greatly narrowed the scope of remedies regarding discrimination.  Discrimination came to be defined as an intentional choice by a prejudiced individual(s), while CRT proponents argue that racism is not a series of isolated acts, but is deeply embedded legally, culturally, and psychologically into the fabric of our society.  Although CRT developed in law schools, it has become a lens with which to view other aspects of society, such as education, housing, and employment.  For an excellent discussion of CRT, read this UU World article by Crystal Fleming.