The top U.S. Catholic bishop vowed legislative and court challenges Tuesday to a compromise by President Barack Obama to his healthcare mandate that now exempts religiously affiliated institutions from paying directly for birth control for their workers, instead making insurance companies responsible.

Cardinal-designate Timothy Dolan, who heads the U.S. Conference of Catholic Bishops, said in an interview with The Associated Press that he trusted Obama wasn't anti-religious and intended to make good on his pledge to work with religious groups to fine-tune the mandate.

"I want to take him at his word," Dolan said in Rome, where he will be made a cardinal Saturday. But he stressed: "I do have to say it's getting harder and harder," to believe Obama's claim to prioritize religious freedom issues given the latest controversy.

Obama sought to quell fierce election-year outrage on Friday by abandoning his stand that religiously affiliated institutions such as Catholic hospitals and universities must pay for birth control. Instead, he said insurance would step in to provide the coverage.

The administration's initial position had outraged evangelicals and Catholic bishops and emboldened many Republicans who charged that it amounted to an assault on religion by forcing religious institutions to pay for contraception, sterilization and the morning-after pill against their consciences.