Political science is an excellent choice for your bachelor degree because much of what you do as a lawyer will involve interpreting local, state and federal laws. For example, if you decide to specialize in representing clients whose constitutional rights were violated, your political science degree can help you understand what certain amendments mean.
If you prefer to defend or prosecute criminals, then an undergraduate degree in criminal justice is a good choice. As a lawyer, you'll have to understand both the rights of victims and criminals, what evidence belongs in certain cases, and how to gather witnesses for a trial.
A bachelor's degree in sociology is beneficial for law school because you'll need to understand how certain groups of people relate to the legal system. For example, if you decide to become a civil rights attorney and represent clients who experienced job or housing discrimination, your sociology background will help.
If you have a bachelor's degree in psychology, you could still use it for law school because as a lawyer you'll have to understand the motives of why criminals committed certain crimes or about the relationship between the criminals and their victims.
If you're a college freshman and are considering law school, think about choosing a major that will help you in a specific area of your future legal career rather than a generalized legal career. Seek help from your campus academic advisor or career counselor if you have trouble deciding.