Term limits must be set for Senators and Congressmen.
It seems that many Senators and Congressmen far too easily forget that they are supposed to be the "voice" of their constituents, the people.
Often times, many tend to all too quickly toss that ideal away and instead pursue their own interests and agendas, and covet/lust for their own power at the expense of their constituents and even the country.
Term limits would help curb this sort of favor-exchanging and corrupt behavior, and the voice of the people would once again be heard.