No member of congress shall assume the office of president by popular election who has served in congress within five years of assuming the office of president.

The US needs this, or something similar, because of the violation of the principle of balance of powers. Members of congress has political entanglements with their associates in congress. When a congressman goes straight from congress to president they carry with them those political entanglements. This violates the most critical principle of checks and balances between the branches of government, in this case the executive and legislative.

Without this amendment we will from time to time have issues like we have today where the president is effectively a mouthpiece for the dominant party in congress. Our system of checks and balances is effectively crippled. Legislation is passed without earnest and credible critique.

A period of time, say five years, should pass between serving in congress and serving as president.  Five years would be about right.  That would be one full presidential term plus one year.  That would be enough to demonstrate the earnestness of the candidate. At the same time it would allow the US to benefit from having qualified people run for the executive office.

Stumble it!