Contrary to the premise, Rhode Island was the last of the original thirteen states to ratify the U.S. Constitution—on May 29, 1790, over a year after the new government began operations.
Rhode Island's resistance stemmed from distinct political culture and economic interests:
By 1790, the new federal government imposed tariffs on Rhode Island goods as if it were a foreign nation. Commercial isolation, pressure from Providence merchants, and the looming threat of the Bill of Rights (which addressed anti-Federalist concerns) forced a second convention.
The ratifying convention approved the Constitution 34–32—the closest margin of any state. Rhode Island entered the Union with a list of proposed amendments, most later incorporated into the Bill of Rights.
Its reluctance reflected genuine fear of consolidation; its eventual assent completed the original union.