The President is limited to two terms in office, to maintain that the USA is democratic, not monarchistic. This ideal should also be applied to Congress.
Currently, 234 of 535 members of the House and Senate have served in office over 10 years, 115 members have served over 20 years.
The establishment of 'career politicians' in Washington has led to the unwillingness to compromise of its members and dysfunction of the body that has contributed to the current economic crises.
Placing term limits of max. 12 years (2 Senate terms, 6 House terms) on Congress may cause members to focus on the good of the country versus the "good" of getting reelected