I've always said that term limits should be instituted. I see no negative to having them as long as it is done correctly.
I'm sure someone smarter than me can determine the finer points, but here is something that is feasible, I think:
a. No more than 5 terms as a U.S. Representative (10 years max)
b. No more than 2 terms as a U.S. Senator (12 years max) - serving at least 1 term in Congress should be a prerequisite for serving as a senator
c. No more than 2 terms as a Vice President (8 years) - I mistakenly assumed that there was already a stated term limit for a VP, but there isn't....so we'd need to nail it down
d. No one can be sworn into a term after their 70th birthday as a representative or a senator
e. No one can be sworn into a term after their 72nd birthday as a POTUS or V.P.
If you hit the "powerball" of federal elections and maxed out all of your possible terms, the absolute most you could ever serve is 38 years in the federal government and you would have to be completely out of the public realm by the age of 76. The age limits for being sworn in should not be seen as some type of ageism slight against older folks......but we got to stop somewhere.....at some point people need to let go and let the next generation take a crack at it. Like I said, someone smarter than me can figure out the finer points.
A question for those smarter than me: If the federal government will not get on the same sheet of music and pass term limits, what if some states stepped up to the plate and limited a candidate's appearances on their ballots after they've been elected a given amount of times. I know that might not be realistic, but is that possible?
www.snipershide.com 
