Roger Williams (c. 1603—1683) was an English Protestant theologian who was an early proponent of religious freedom and the separation of church and state. In 1636, he began the colony of Providence Plantation, which provided a refuge for religious minorities. Williams started the first Baptist church in America, the First Baptist Church of Providence. He was a student of Native American languages and an advocate for fair dealings with Native Americans. Williams was arguably the very first abolitionist in North America, having organized the first attempt to ban slavery in any of the original thirteen colonies. (Source)
This Wikipedia article is worth reading. Williams was a strong and early advocate of freedom of religion and separation of church and state. His ideas probably influenced the principles expressed in the First Amendment of the US Constitution.
Buddhists, and others, would do well to reflect on the great importance of the First Amendment, which reads:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
“Religion” means something different today than it did during Williams’ life, but Williams’ underlying belief that each individual must be free to follow their own religious convictions is as fundamentally important today as it was back then.
American Buddhists obviously benefit from these protections, but even hard atheists and those who dislike all religions should ponder the profound importance of the individual right to believe what you want and to profess your beliefs without interference from the state.