Although there are many people who think term limits for members of Congress are a good thing, political scientists tend to argue that they would actually detract from the level of democracy in our system. Implementing term limits would result in more power flowing to unelected people.
Congress has to deal with a large variety of incredibly complicated issues. They have to think about how to reform the tax code. They have to think about what to do about Medicare. They have to think about how to change regulations so as to improve the economy. All of these are very complex issues. In order to become truly knowledgeable about even one or two of these issues, a person has to spend a lot of time learning. This is much more possible for members of Congress if they can stay in office indefinitely.
If members of Congress were term limited, the fear is that they would not have time to learn. This would mean that all of the experts would be unelected. They would be the members of the Congressional committees’ staffs. They would be members of lobbying groups. Members of Congress would have to lean on these people to tell them the things that they do not have time to learn on their own. Since these people are not elected officials, the level of democracy in our system would be reduced.
Thus, far from bringing more democracy, term limits would (many political scientists think) reduce democracy by giving more power to people who are not elected.