A POTUS should not be sworn in using a bible, it actually violates the anti establishment clause of the first amendment of the United States Constitution, this also goes for "in god we trust" minted on coins and printed on currency bills.
@Carla Not to mention forcing foreign exchange students to recite the pledge of allegiance in public schools, despite the US Supreme Court ruling forced recitation unConstitutional in 1943 that was started by a group of Jehovah's Witnesses.