In the next general election, have a ballot on term limits for members of US Congress. Although popular vote cannot change the Constitution, the results can let Congress know how the American people feel about term limits in their office. If the result is overwhelmingly for term limits, then Congress itself may pass this into law.
I believe unlimited terms in any elected office should not exist. Many people get re-elected based on the familiarity of their name. The incumbant generally gets their party's nomination. If you have never seen the (old) movie Mr. Smith Goes to Washington, you will see how fresh faces and ideas can bring about positive change.
By signing this petition, you are not agreeing that there should be limits or not. You are only asking for a popular vote.