When Jim Webb did not run for reelection in 2012, Mark Warner, who is still in his first term (2009-2015), became the senior senator from Virginia.
Warner is a Democrat and the senior Senator from Virginia.
For the six-year term from 2015 to 2021Mark Warner (D - VA), senior senatorFor the six-year term from 2013 to 2019Tim Kaine (D- VA), junior senator
Each state has 2 senators. The one who has been in office the longest is the senior senator.
Robert Byrd.
Mark Warner has won the votes for senator in Virginia.
Yes she is the senior Senator and Susan Collins is the junior Senator.
The Governor
Mark Warner from Virginia is a US senator.
Bill Nelson (D) is the senior US Senator from Florida.
Sen. Richard J. Durbin (D-IL). He is also the current Majority Whip.
The difference is that the senior Senator has been in office longer than the junior Senator.
The current (2010) Senate Majority Leader is Harry Reid and the President Pro Tempore who by custom is the Senior Senator is Robert Byrd.