Carroll was born into a prominent Irish Catholic family of Maryland. He received an excellent parochial education, studying for six years under the Jesuits in Flanders. After touring Europe he returned to his home colony but took no active role in public life until 1781. In that year he was elected to the Continental Congress. Soon after he began a lifelong career in the Maryland Senate. Carroll did not take his seat at the Philadelphia convention until July 9, but he attended regularly after that, took the floor to speak on several occasions, and served on the influential Committee on Postponed Matters. Carroll won a seat in the first U.S. House of Representatives, where he voted for most Federalist measures. In 1791 his friend George Washington named him to the commission to survey and define the District of Columbia, an area in which Carroll held extensive land. Bad health forced him to resign from this post after four years, and he died soon afterward.
A man of consistent good humor, Jenifer inherited a large estate near Annapolis, where he lived in comfortable bachelorhood for the rest of his life. As a young man, Jenifer held a variety of appointive offices for the proprietors of Maryland. During the early 1770s, he served in the royal governor's council. Despite his long association with the proprietors and the Crown, Jenifer supported the independence movement. He served as president of the first state senate of Maryland, and he sat in the Continental Congress from 1778 to 1782. A strong nationalist, he was an early supporter of granting the power to tax to the central government. He attended the Mount Vernon conference as well as the Philadelphia convention. Although he rarely spoke at the Constitutional Convention, he supported Madison on almost every occasion. After the convention Jenifer retired from public office.
One of the most controversial figures at the Philadelphia convention, Martin was a complex and tragic figure. He graduated with honors from the College of New Jersey, taught school in Maryland for a few years, and then studied law in Virginia before making his home in Maryland. He was an early advocate of independence and served on several patriotic committees before the war began. He was highly successful as a lawyer and was named attorney general of Maryland before he was thirty. He was known for his generosity to poorer clients, but also for his rudeness toward men of his own social class. He became increasingly eccentric, however, sometimes appearing disheveled and often appearing drunk in public. At the Philadelphia convention, Martin was an immediate and consistent opponent of the Constitution, voting against the Virginia Plan and questioning the decision that the convention's meetings be held in secret. When he took the floor to speak, he often engaged in loud and long harangues, delivering a three-hour speech at a crucial moment in the debates over representation. He eventually walked out of the convention before it adjourned, joined by fellow delegate John Francis Mercer. During the ratification struggle, Martin campaigned vigorously against the adoption of the Constitution, opposing the increased power of the central government over the states, proportional representation in the House, the inclusion of slaves in determining state populations, and the absence of a jury in Supreme Court deliberations. His criticisms reflected the fundamental Anti-Federalist position. Yet by 1791 Martin had joined the Federalist camp, driven there by his hatred of Thomas Jefferson. Throughout the rest of his career, Martin did not flinch from taking on controversial legal cases. He successfully defended his friend Supreme Court Justice Samuel Chase when Chase was impeached, and he served as a defense lawyer for Aaron Burr when Burr was on trial for treason in 1807. A brilliant lawyer, Martin argued Maryland's position in the landmark Supreme Court case McCulloch v. Maryland. In his last years, however, heavy drinking and illness diminished Martin's fortune and his reputation. He suffered a paralysis in 1819 that forced him to retire as Maryland's attorney general, and he died a poor man in 1826.
McHenry was born in Ireland and received a classical education in Dublin. He arrived in America in 1771, and the following year the rest of his family immigrated here as well. While his father and brother established an importing business, McHenry studied medicine with the well-known Philadelphia physician Dr. Benjamin Rush. During the Revolution McHenry served as a military surgeon. He was captured by the British in late 1776 but was exchanged in March 1778. He was assigned to Valley Forge and became General Washington's secretary. His work for Washington may have influenced McHenry's decision to give up the practice of medicine for the world of politics and administration. He remained on Washington's staff until 1780 and then went on to serve the marquis de Lafayette. He had a seat in the Continental Congress from 1783 to 1786. McHenry missed much of the Philadelphia convention because of his brother's illness and contributed little to the debate when he was there. He was a firm nationalist, however, and campaigned for ratification of the Constitution in his home state. In 1796 McHenry accepted President Washington's appointment as secretary of war, a position he continued to hold during John Adams's administration. McHenry's preference for Hamilton's political guidance rather than Adams's annoyed the president, and in 1800 Adams forced the Marylander to resign. McHenry's political career thus ended, but he remained a firm Federalist and thus opposed the War of 1812.
Born in Virginia, Mercer attended the College of William and Mary. When the Revolution began, he joined the Third Virginia Regiment and became General Charles Lee's aide-de-camp in 1778. When Lee was court-martialed, Mercer resigned his commission and took up the study of law. In 1782 Mercer was elected to the Virginia House of Delegates and soon after to the Continental Congress. In 1785 he moved to Maryland and attended the Philadelphia convention as a Maryland delegate. At twenty-eight, he was among the youngest men there. Like Luther Martin, Mercer was a strong opponent of centralization of government, and he spoke out against the Constitution during the convention, ultimately leaving the convention before it was signed. In the 1790s Mercer aligned himself with the Democratic-Republican Party of Jefferson and Madison. He served in the U.S. House of Representatives from 1791 to 1794 and served two terms as governor of Maryland in the early nineteenth century. When Jefferson became president, Mercer renounced the Democratic-Republicans and joined the Federalist camp.
The delegate biographies are excerpted with the generous permission of Carol Berkin, author of A Brilliant Solution: Inventing the American Constitution (Harcourt). Copyright © 2002 by Carol Berkin.