Sen. Byrd, D-WV,  was President Pro Tempore of the Senate, meaning he was 3rd in the line of succession to the presidency after Vice President Biden and then Speaker Pelosi, D-CA.

The position goes to the longest serving member of the Senate in the Majority party.

With Byrd's death, his longtime friend, Senate Appropriations Committee Chairman Daniel Inouye, D-HI, a WWII veteran, takes over now, with 47 years of service under his belt.

Inouye was third in the line of seniority last year, but with the passing of Sen. Ted Kennedy, D-MA, the second most senior Democrat, Inouye moves up.