By 1804, Vice President Burr had thoroughly alienated Jefferson, and the Democratic-Republican presidential nominating caucus chose George Clinton as Jefferson's running mate for the 1804 presidential election. That same year, Burr challenged Hamilton to a duel after taking offense to a comment allegedly made by Hamilton; Hamilton died in the subsequent duel. Bolstered by a superior party organization, Jefferson won the 1804 election in a landslide over Federalist candidate Charles Cotesworth Pinckney. In 1807, as the Napoleonic Wars continued, the British announced the Orders in Council, which called for a blockade on the French Empire. In response to subsequent British and French attacks on American shipping, the Jefferson administration passed the Embargo Act of 1807, which cut off trade with Europe. The embargo proved unpopular and difficult to enforce, especially in Federalist-leaning New England, and expired at the end of Jefferson's second term. Jefferson declined to seek a third term in the 1808 presidential election, but helped Madison triumph over George Clinton and James Monroe at the party's congressional nominating caucus. Madison won the general election in a landslide over Pinckney.