What is remarkable about PJ Crowley's expression of disagreement with the treatment of Bradley Manning (Report, 12 March) is that he has not been joined by others from the US government. In the diplomatic, intelligence and military services, there is considerable dissent from the policies of the White House, specifically, from its continuation of the violations of the US constitution and international norms of civil and human rights begun by the preceding administration. Given what these persons say to their families and friends, one would expect a few more to come forward and break a silence which is increasingly noxious.

Norman Birnbaum

Washington DC

• You report the resignation of PJ Crowley following his description of the conditions under which Bradley Manning is detained (Report, 14 March). Those conditions, imposed on an unconvicted prisoner who is also a British citizen, have included solitary confinement, repeated waking, enforced sleeping positions and being required every day to parade naked in his cell. Under the pretext of suicide risk – apparently denied by the prison psychologist – his glasses and clothes have at times been confiscated. President Obama has now said he has been "reassured" by the Pentagon that Manning's confinement is appropriate. Manning is accused of passing the US "embassy tapes" to WikiLeaks.

Here in the UK, the US is seeking extradition of Gary McKinnon on charges of prejudicing US national security by hacking into Pentagon computers. Prison sentences of up to 60 years have been mentioned. There are many factors in McKinnon's case – his state of health and the unbalanced nature of the extradition treaty among them – but the treatment of Manning must surely mean there can now be no further question of his being delivered into US custody.

Roger Hallam

London