ATLANTA (AP) — The pope's U.S. ambassador praised American bishops Wednesday for confronting the government over religious liberty issues, including resisting the mandate from President Barack Obama's administration that health insurance cover birth control.

Archbishop Carlo Vigano, the papal nuncio based in Washington, noted that the advocacy required a "delicate" approach in the context of a presidential election. But Vigano said the concerns were so worrisome that bishops had to act.

"It goes without saying that the Catholic Church in the United States is living in a particularly challenging period of its history," Vigano told an Atlanta meeting of the U.S. Conference of Catholic Bishops. "Of course, I am thinking of the whole question of freedom of religion and of conscience."