NO RELIGIOUS TEST SHALL BE REQUIRED FOR THE EXERCISE OF CIVIL AND POLITICAL RIGHTS.Taken at face value "the exercise of civil and political rights" covers the entire moral universe that every citizen exists in under the present Constitution. That no religious test shall be required, for the exercise of citizen's rights, clearly defines the relationship between Religion and Government in the form of a PROHIBITION against applying any THEOLOGY to determine whether to allow the exercise of a civil or poliitcal right, such as the right to vote or be elected into office. Indeed all of our rights to life, liberty, and the pursuit of happiness (which 1987 calls "security"), all of our civil and political rights may be exercised freely without any requirement to pass some religious test or judgment from Theology--only the Morality represented by the Constitution itself.
The Principle at the very heart of Separation of Church and State is, in my opinion, much easier to see through the lens of the No Religious Test clause, than for example through the Non-Establishment clause. ("No law shall be passed respecting an establishment of religion, or prohibiting the free exercise thereof.")
In the No Religious Test clause we see clearly defined the relationship between Theology and Morality under the Constitution: namely: NONE. The Constitution is all Morality but no Theology.