Snowden has been charged with espionage and while prominent Democrats and Republicans in the US have called Snowden a traitor for leaking details of the government's electronic surveillance programme, Humphrey has called Snowden a courageous whistleblower. He has prevailed upon Sweden to give Snowden asylum.
Humphrey tells Radio Sweden: "Sweden has a long tradition of independence and idealism in its policies towards human and civil rights and has a long, established record of offering asylum to people like Mr Snowden, who has become stateless by virtue of the US revoking his passport."
Humphrey claims Snowden is in danger in Russia, even if he has been granted temporary asylum there.
"Mr Snowden will become the target of the Federal Security Office in Russia and he is in danger in a second respect, too. The US will continually try to find a way to persuade the Russian government to make a deal to hand him back," says Humphrey.
Humphrey has been in email contact with Snowden, but said the whistleblower has not responded to his suggestion that he should apply for asylum in Sweden.
He sees no risk of Sweden handing over Snowden to the US were he to come to Sweden.