VATICAN CITY -- The last U.S. ambassador to the Vatican was ordered to leave Rome two years after the end of the American Civil War.
Despite the break, Washington and the Vatican have maintained unofficial on-again, off-again ties since the founding of the United States.
The first recorded diplomatic contact occurred in 1783 in Paris at the end of the American Revolution, Vatican historians said.
The French papal nuncio gave Benjamin Franklin a message from Pope Pius VI, conveying his best wishes for the new country and opening the Papal States' ports to U.S. ships.
President Abraham Lincoln asked Pope Pius IX to name the first U.S. cardinal, church historians said.
President Reagan's current personal envoy to the Vatican, William Wilson, is to be nominated to the new diplomatic post. If Congress confirms him, Wilson will be Washington's first official ambassador since Rufus King Jr. was ordered to leave Rome in 1867.
President Harry Truman tried to re-establish formal diplomatic ties with the Vatican in 1952, but Congress raised such a storm of protest he quickly dropped the idea.
Following Congress' embarrassing rebuff to Truman, Presidents Eisenhower, Kennedy and Johnson chose not to name a personal representative.
Nearly 20 years passed before President Nixon revived the practice with his 1970 appointment of former U.S. Ambassador to Saigon Henry Cabot Lodge to the unofficial post. Lodge continued serving under President Gerald Ford.
President Carter -- disappointing strict church-state separationists and his own 12-million member Southern Baptist Convention -- named Miami attorney David Walters his personal representative in 1978.
Walters, who resigned a year later, was replaced by former New York City Mayor Robert Wagner.
The last official U.S. ambassador to the Vatican was forced out by an 1867 Congressional decision cutting all funds to the American legation in Rome on grounds the Vatican had ordered the American Protestant church in Rome to move outside the city's walls.
Ambassador King denied such an order was given but Congress cut all funding anyway, a move that neatly and simultaneously cleared the way for Washington's subsequent recognition of the emerging modern Italian state.
Congress voted the cuts the same year Giuseppe Garibaldi, 'the Father of Modern Italy,' defeated the papal army and took temporary control of Rome.
It took three more years, until 1870, for Italian troops to end the temporal power of the popes and take virtually all the territory belonging to the Papal States, leaving only tiny Vatican City under papal control.