Shortly before noon Tuesday, Vermont Senator Patrick Leahy was sworn in as the Senate President Pro Tempore.
Vice President Joe Biden administered the oath.
"Do you solemnly swear that you’ll support and defend the constitution of the United States against all enemies, foreign and domestic … That you bear true faith and allegiance to the same … That you take this oath and obligation freely without any mental reservation or purpose of evasion and that you will well and faithfully discharge the duties of the office on which you are about to enter so help you God?"
Leahy replied, "I do, so help me God."
The Pro Tem position is largely ceremonial. But the position makes Leahy the third in the line of presidential succession, behind the vice president and the speaker of the House.
Leahy is in his seventh term, and became the most senior member of the Senate following the death yesterday of Hawaii Senator Daniel Inouye.
Leahy is also in line to replace Inouye as chairman of the Senate Appropriations Committee. The 72-year-old Leahy currently chairs the Senate Judiciary Committee.