Iranian scientist Samira Asgari was one of many people from around the world caught in President Donald Trump’s executive order banning people from seven Muslim-majority countries from entering the U.S. On Saturday morning, Asgari was scheduled to fly from Frankfurt to Boston, where she had a visa to work as a post-doctoral fellow at Brigham and Women’s Hospital, to study the relationship between genetics and tuberculosis. But before she could board her flight, she was stopped by an U.S. consular officer who said her visa was no longer valid because of Trump’s order.

“The shock wore off yesterday evening,” Asgari told The Atlantic on Sunday. “Now there’s just extreme sadness, and a very strong feeling that I’ve been discriminated against. Even in Iran, you have this picture of America as a dreamland. But for people like me, this isn’t the America we imagined.”

Asgari’s disillusionment with America suggests what will be the most lasting impact of the temporary refugee ban: that it tarnishes America’s claim to be a progressive country, the land of the future. As a piece of policy, the order, reportedly crafted by the ultra-nationalist ideologues Steve Bannon and Stephen Miller in defiance of career bureaucrats at the department of Homeland Security, is politically vulnerable. The Trump administration is already walking back key parts of the policy. “As far as green card holders, moving forward, it doesn’t affect them,” Reince Priebus, the White House chief of staff, said on Sunday’s Meet the Press. Homeland Security Secretary John Kelly later released a statement saying, “In applying the provisions of the president’s executive order, I hereby deem the entry of lawful permanent residents to be in the national interest.”

Politically, the ban is proving to be a costly failure for Trump, both because of the opposition it has generated and because of its incompetent execution. Even some key members of Trumps’s own party, who have been so tolerant of his bigotry and poor handle on policy, feel emboldened to criticize him. “I think we need to be careful,” Senate Majority Leader Mitch McConnell said. “We don’t have religious tests in this country.” Senator John McCain said, “Ultimately, we fear this executive order will become a self-inflicted wound in the fight against terrorism.” Senator Rob Portman called the ban “an extreme vetting proposal that did not get the vetting it should have had.” In a statement, New Jersey Congressman Leonard Lance said, “the president’s current travel ban executive order appears rushed and poorly implemented.”

A wide range of Christian leaders have also denounced the ban. Leaders of the evangelical community, who make up one of Trump’s crucial voting blocs, sent a letter to the president saying they were “troubled” by the ban and calling for refugee resettlement to resume. Cardinal Blase Cupich of Chicago was blunter in his condemnation. “This weekend proved to be a dark moment in U.S. history,” Cupich said in a statement. “The executive order to turn away refugees and to close our nation to those, particularly Muslims, fleeing violence, oppression and persecution is contrary to both Catholic and American values.... The world is watching as we abandon our commitments to American values. These actions give aid and comfort to those who would destroy our way of life. They lower our estimation in the eyes of the many peoples who want to know America as a defender of human rights and religious liberty, not a nation that targets religious populations and then shuts its doors on them.”