Brevity is part of the glory, and maybe a part of continual differences in interpretation, of the Bill of Rights. The 12th Amendment is not so brief. It is also more technical in nature, trying to correct the problem of governance caused by having a President of one party (i. e. political philosophy) and a Vice President of a vastly different one. The effectiveness of John Adams's presidency was certainly impacted by having Thomas Jefferson as his Vice President. The Twelfth Amendment was ratified on June 15, 1804. Our presidential elections still follow its guidelines. If you care to read the text of Amendment XII, go here.