The requirements owner (RO) is questioning contracting on whether or not to add/remove a statement in their PWS on whether a Catholic Priest should be a US citizen. Previous requirement indicated that there was a lack of interest in this requirement and it was difficult to find somebody to fill in while the permanent military Priest did several deployments and then R&R when he returned.
It is our opinion that you should not require U.S. Citizenship, this would be an unnecessary and overly restrictive term and condition for a religious services contract on an installation. There is not DoD Instruction or regulation (including the DFARS) which mandates religious service personnel be U.S. Citizens.
Rationale: There is little chance any information the priest would receive or have access to would be subject to Export Control (see DFARS subpart 225.79).
As long as the Priest is legally authorized to reside in and work in the U.S. you should be fine, that would be determined by making sure you follow the requirements of FAR subpart 22.18 when building your solicitation and evaluating offers. This is complying with the DHS E-verify requirements. Note there is no DFARS implemental or supplemental language. They will also have to pass your installations access requirement and background checks.
That said, do not forget to review DFARS 237.77 Religious Services prior to doing market research or developing your solicitation.