Related Rule
United States of America
Practice Relating to Rule 125. Correspondence of Persons Deprived of Their Liberty
The US Field Manual (1956) reproduces Articles 70 and 71 of the 1949 Geneva Convention III and Articles 25, 106 and 107 of the 1949 Geneva Convention IV. 
United States, Field Manual 27-10, The Law of Land Warfare, US Department of the Army, 18 July 1956, as modified by Change No. 1, 15 July 1976, §§ 146, 147, 264, 313 and 314.
The US Instructor’s Guide (1985) provides: “Even though you are a prisoner (or internee), you are entitled to send and receive mail. Each prisoner must be allowed to write a minimum of two letters and four postal cards per month.” 
United States, Instructor’s Guide – The Law of War, Headquarters Department of the Army, Washington, April 1985, p. 11.
The US Air Force Pamphlet (1976) provides: “The prisoner of war shall be permitted to send out a capture card addressed to the Central Prisoners of War Agency for its card index system.” The Pamphlet further specifies that Article 71 of the 1949 Geneva Convention III entitles them “to mail a minimum of 2 letters and 4 cards each month”. It adds: “This minimum may be reduced if the protecting power finds that to be required by necessary censorship. POWs are also allowed to send telegrams under certain circumstances.” 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 13-7.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that no prisoner of war in the hands of Iraq “was permitted the rights otherwise afforded them by [the 1949 Geneva Convention III], such as the right of correspondence authorized by Article 70”. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, p. 630.
According to the Report on US Practice, “Articles 4, 5 and 6 [of the 1977 Additional Protocol II] reflect general US policy on treatment of persons in the power of an adverse party in armed conflicts governed by common Article 3” of the 1949 Geneva Conventions. The report also notes: “It is the opinio juris of the US that persons detained in connection with an internal armed conflict are entitled to humane treatment as specified in Articles 4, 5 and 6 [of the 1977 Additional Protocol II].” 
Report on US Practice, 1997, Chapter 5.3.
In August 2003, the US State Department issued a written response to an opinion issued by the United Nations Commission on Human Rights (UNCHR), dated 8 May 2003, that had referred to a UNCHR Working Group report on Arbitrary Detention, dated 8 January 2003, which was critical of US policy regarding detainees held at the US naval bay at Guantanamo Bay, Cuba. In disagreeing with the UNCHR reports, and noting that the competence of the Working Group did not extend to the laws and customs of war, the US response stated:
Detainees are also permitted to communicate with family and friends at home via letters and postcards. They use either the U.S. military postal service, or the ICRC, which delivers mail via its offices in each country. The volume of communications is not insubstantial; from January 2002 (when detainees first began to arrive) to July 2002, the United States military delivered over 1,600 pieces of mail sent out by detainees and delivered over 300 pieces of mail sent to detainees. 
United States, State Department, Response to UNCHR Opinion No. 5/2003 of 8 May 2003 and the Communication of 8 January 2003 of the Working Group on Arbitrary Detention, August 2003.
In March 2006, the US Government issued a written response to a report produced by a group of five special rapporteurs to the United Nations Commission on Human Rights, dated 16 February 2006, which was critical of US policy regarding detainees held at the US naval base at Guantanamo Bay, Cuba. The US Government’s response stated in part:
[Detainees are provided with] the means to send and receive mail, including confidential mail for those detainees who have appointed counsel. Over 43,120 pieces of mail have either been sent or received by detainees at Guantanamo since it was opened. Some 18,580 pieces of mail were processed in calendar year 2005. 
United States, Reply of the Government of the United States of America to the Report of the Five UNCHR Special Rapporteurs on Detainees in Guantanamo Bay, Cuba, 10 March 2006, p. 6.