“History I believe furnishes no example of a priest-ridden people maintaining a free civil government. This marks the lowest grade of ignorance, of which their political as well as religious leaders will always avail themselves for their own purpose. “ — Thomas Jefferson to Baron von Humboldt, 1813
While Jefferson clearly embraced the ideas which Bellarmine expressed in De Laicis, he obviously was not Catholic himself.
There are a number of quotes that show up along with the one you have posted from Jefferson’s letter to Baron Von Humboldt. I don’t have time to do the research to find all the letters pertaining to Jefferson’s discussion with Von Humboldt. The particular quote you have posted appears to pertain the necessity of separation/independence between the altar and the throne. Unfortunately, Jefferson’s writing style in many of his letters is often misunderstood without reading the whole letter as well as the letter or issue he was responding to when he wrote it. One must also keep in mind his continued actions..... this leads to the letter to the Danbury Baptists Association. Many atheists claim the wall of separation means there should be no expression of religious belief in the political arena. Which is not what he meant in either his word or actions. He did not want the government establish an official religion and have religious tests for employment by the government as was done with the Church of England. He clearly saw no issue with prayer in the public square or in public buildings as evidenced by the fact that he regularly attended Sunday religious services in the House Chambers of the Capital Building while he was President.