swissinfo.ch and agencies
Ramadan has had his US visa revoked several times since 2004 when he was due to take up a university teaching post. He was banned from the US over alleged ties to terrorism.
Secretary of State Hillary Rodham Clinton has signed orders enabling the re-entry of Ramadan and Adam Habib, a professor at the University of Johannesburg in South Africa, once they obtained required admittance documents, department spokesman Darby Holladay said on Wednesday.
He said Clinton â€œhas chosen to exercise her exemption authorityâ€ for the pairâ€™s benefit. â€œBoth the president and the secretary of state have made it clear that the US government is pursuing a new relationship with Muslim communities based on mutual interest and mutual respect,â€ Holladay said.
Both professors, who are frequently invited to the US to lecture, were critics of the war in Iraq.
Government lawyers have said Ramadan was barred because he gave money to a Swiss-based charity, the Association de Secours Palestinien (ASP), between 1998 and 2002. Washington listed ASP as a banned group in 2003, saying it supported terrorism and had contributed funds to the Palestinian Islamic movement Hamas.
â€œThe decision brings to an end a dark period in American politics that saw security considerations invoked to block critical debate through a policy of exclusion and baseless allegation,â€ Ramadan said in a statement.