A Senate Commerce Committee hearing on interoperable public-safety communications scheduled for this afternoon was postponed, apparently so senators could attend the swearing-in ceremony for new Supreme Court Chief Justice John Roberts.

Scheduled to begin at 2:30 p.m. EDT, the postponed session has not been rescheduled, according to a person in the Senate committee’s office. No official explanation for the postponement was given, but a source associated with one of the witnesses scheduled to give testimony said the measure was taken so that senators could attend Roberts’ ceremony this afternoon.

Executives for Motorola, M/A-COM, Mobile Satellite Ventures and Iridium Satellite were scheduled to testify during the afternoon session of a hearing entitled “Communications Interoperability.”