George Mason significantly influenced the creation of the Bill of Rights primarily through his refusal to sign the United States Constitution. He was a key figure at the Constitutional Convention in 1787 and expressed strong concerns about the lack of explicit protections for individual liberties in the proposed Constitution.
His objections, along with those of other Anti-Federalists, highlighted the need for a Bill of Rights to safeguard personal freedoms. Mason's reluctance to endorse the Constitution unless it included these protections played a pivotal role in the subsequent push for a Bill of Rights, which ultimately led to the adoption of the first ten amendments to the Constitution.
While he did write a pamphlet titled "Objections to This Constitution of Government," his refusal to sign the Constitution is the most directly impactful action he took regarding the Bill of Rights. Thus, both his refusal to sign and his pamphlet contributed to the discourse surrounding the need for a Bill of Rights, but the refusal had a more immediate influence on the eventual ratification process.