Simple term limits similar to those imposed on the executive branch.
10 year limit on Congress
12 year limit on Senate
This means adding an additional amendment to the constitution. Simple wording without loopholes. Example: "No member of the United States House of Representatives shall hold office for more than 5 terms or 10 years. No member of the United States Senate shall hold office for more than 2 terms or 12 years."
This would get rid of people that were bought out decades ago for special interests and no longer truly represent their constituencies.