This week, for talks aimed at bridging divisions between the world鈥檚 two largest religions. The gathering, hosted by Pope Benedict XVI, ended with a joint declaration 鈥渞enouncing any oppression, aggressive violence and terrorism, especially that committed in the name of religion, and upholding the principle of justice for all.鈥漈he Pope鈥檚 guests included Tariq Ramadan, the Swiss-born, Oxford-based scholar who, while eminent enough to merit a place at the papal conference table, continues to be persona non grata in the United States.In 2004, Ramadan was preparing to assume a teaching position at Notre Dame when he was told that his visa had been cancelled. At the time, a State Department spokesman said Ramadan was unwelcome in the U.S. under a Patriot Act provision barring those who use a 鈥榩osition of prominence鈥 to 鈥榚ndorse or espouse terrorism.鈥 It was an untenable explanation 鈥 Ramadan has consistently denounced terrorism throughout his career 鈥 but the U.S. has continued to exclude him from the U.S. through a series of strategic stalls and shifting explanations.When joined the 老澳门开奖结果 in challenging his exclusion and the Patriot Act provision, the government retracted its claim that Ramadan endorsed terrorism, but said it needed more time to decide his fate. The judge disagreed, ordering the government either to grant him a visa or give a legitimate reason for excluding him. With the court鈥檚 deadline looming, the government then asserted Ramadan was inadmissible because he had provided 鈥榤aterial support to terrorism.鈥 It cited donations Ramadan had made to a Palestinian charity in Switzerland in 1999 and 2000 totaling around $1,000, a charity which the U.S. added to its terror watch list in 2003 but which still operates legally in Europe.We went back to court to challenge this new pretext. This time the judge said his hands were tied 鈥 that the government had given a reason for the exclusion, and that, even though in 2000 the U.S. itself hadn鈥檛 yet concluded that the charity was involved in anything other than relief work, Ramadan hadn鈥檛 proved he didn鈥檛 know his donation was supporting terrorism. How does a person prove he didn鈥檛 know something?We鈥檙e now appealing that decision. If it stands, tens of thousands of foreigners could find themselves barred from the United States because they made donations in good faith to organizations the U.S. later alleged have connections to terrorists. Among them there are likely to be many Tariq Ramadans, international writers and scholars who are major participants in some of the most critical conversations of our time, men and women whose exclusion from the United States violates our rights as American citizens to hear these voices face-to-face and engage directly in these conversations.These conversations are happening, whether we鈥檙e part of them or not, and this week鈥檚 gathering at the Vatican shows how valuable and hopeful they can be. The fact that one of the Pope鈥檚 guests cannot visit the U.S., meanwhile, just serves to underscore how out of step and embarrassing this administration鈥檚 practice of ideological exclusion has been.