Department of Homeland Security officials have agreed to revise their naturalization tests following pressure from a Republican senator who worried they were promulgating a "confined" understanding of religious liberty.

"We live in a great nation that allows individuals to live out their faith, or have no faith at all," Oklahoma Sen. James Lankford said Friday. "To protect freedom and diversity, we must carefully articulate this right throughout the federal government."

To that end, he pressed DHS to revise immigrant study guides that referred to "freedom of worship" rather than "freedom of religion," which conservative Christians regard as more expansive and more consistent with the text of the First Amendment. U.S. Citizenship and Immigration Services initially refused to do so last year, but ultimately reversed course.

"At first glance, it appears like a small matter, but it is actually an important distinction for the Constitution and the First Amendment," Lankford said Friday. "The 'freedom of religion' language reflects our right to live a life of faith at all times, while the 'freedom of worship' reflects a right simply confined to a particular space and location."

DHS seemed to assent to the change without agreeing with Lankford about the significance of the distinction. "We have determined that making this change is feasible because it is a change in terminology rather than an addition or deletion of test content," USCIS director Leon Rodriguez wrote on March 28.

The change affects 40 DHS publications. "In accordance with agency policy, if the applicant's answer to a civics question is an 'alternative phrasing of a correct answer,' U.S. Citizenship and Immigration Services officers will continue to accept both 'freedom of religion' and 'freedom of worship' as correct answers to question 51 when administering the naturalization test," Rodriguez added.