Over at Mises.org, Wendy McElroy laments the world of passport-only travel that has been erected in the wake of 9/11, and discusses the intimate relationship between mandatory papers-checking and war. Excerpt:
America and the world were not always this way. It is important to remember that there once was a world in which people traveled freely across borders without paperwork to visit families, pursue education, conduct business, and mingle. Freedom worked once. It enriched the world economically, culturally, and psychologically. [...]
The American passport was [...] rooted in war, specifically the American Revolution (1775–1783). The first one was issued in 1783; based on the French "passport," it was designed and printed by Benjamin Franklin. [...]
During the Articles of Confederation period (1783–1789), passports were issued but not required. When the US Constitution was ratified, creating a new government, passports continued to be issued but not required. Many American states and cities also issued their own "voluntary" passports until 1856 when the Department of State exerted a federal monopoly, ostensibly to eliminate confusion.
Nevertheless, passports were not mandatory except for a period during the American Civil War (1861–1865) and during World War I (1914–1918). The latter can be seen as the beginning of the current American passport. On December 15, 1915, President Woodrow Wilson issued Executive Order No. 2285, "[r]equiring American citizens traveling abroad to procure passports" and advising theSecretary of State, in co-operation with the Secretary of the Treasury, will make arrangements for the inspection of passports of all persons, American or foreign, leaving this country.
This was followed in 1918 by an act of Congress granting the president authority to require passports during time of war. Passports remained mandatory until early 1921.
Thereafter, the United States continued its "no-passport-required" travel policy until another war: World War II (1939–1945). In 1941, passports became mandatory for travel abroad and remain so to this day. (Travel to Canada used to be an exception; until recently, proof of citizenship was all that was required to cross the border.)
McElroy points out some of the largely unknown ways that the passport requirement is used as social control:
[P]assports can be denied for a myriad of reasons that have nothing to do with being "an enemy of the state" but rest strictly on statutory grounds. Common reasons for denial include owing money to the IRS, a federal arrest, a state-criminal court order existing, a drug arrest, being on parole or probation. Law-enforcement databases are routinely checked against both passports and applications to weed out those who have committed such offenses as being more than $2,500 behind on child-support payments. Passports can also be revoked for several reasons, although revocation is far less common.