The longest serving Senator in history has passed away overnight.  Robert Byrd (D-WV), a controversial figure and third in the line of succession in the current government, died at the age of 92 after a final hospitalization yesterday:

The Senate has lost one of its legends with the death of Robert C. Byrd, an orphan child who married a coal miner’s daughter and rose from the hollows of West Virginia coal country to become the longest serving senator in U.S. history.

He died around 3 a.m. Monday morning after being admitted to the hospital last week for dehydration, yet his condition worsened over the weekend and he became critically ill. Byrd was 92. …

It’s not a stretch to say Byrd wrote the book on the U.S. Senate — he authored a four-volume history of the upper chamber — which is why so many of his younger, more energetic colleagues continued to defer to him when it came to Senate rules and procedures.

Byrd had been hospitalized on and off over the past two years, including an extended hospitalization back in March. He was rarely seen in the Senate in recent months, yet he made it to several key floor votes over the past year.

The timing of Byrd’s death creates the need for a special election, as Nate Silver explained before Byrd passed away:

Byrd’s current term expires on January 3, 2013. Under West Virginia state law on handling Senate vacancies, “if the vacancy occurs less than two years and six months before the end of the term, the Governor appoints someone to fill the unexpired term and there is no election”. Otherwise, Manchin would appoint an interim replacement, and an special election would be held in November to determine who held the seat in 2011 and 2012.

In other words, we are within a week of the threshold established by West Virginia law. If a vacancy were to be declared on July 3rd or later, there would not be an election to replace Byrd until 2012. If it were to occur earlier, there could potentially be an election later this year, although there might be some ambiguities arising from precisely when and how the vacancy were declared.

Manchin, a Democrat, reportedly wanted a shot at the seat himself when Byrd left the Senate.  That would be a difficult maneuver now, at least in terms of the interim appointment.  Had Byrd died a week later, Manchin could have appointed himself to what would have been a two-year term and hoped to ride Barack Obama’s coattails, such as they will be, into a full term in 2012.  Now the election will have to be held this year in a midterm cycle poisonous to Democrats, especially in coal country while the Senate attempts to revive cap-and-trade.

As for Byrd, his death does mark the end of an era and removes a continual flashpoint for controversy.  Byrd’s history as a KKK recruiter and the man who filibustered the Civil Rights Act was routinely cited by Republicans and excused by Democrats.  Ironically, he was the last member of the upper chamber from those days.  Byrd also attracted controversy as one of the biggest practitioners of pork-barrel politics in Congress, which endeared him to many West Virginia voters but made him the scourge of clean-government and fiscal-responsibility activists.  The media treated him with a bit of amnesia regarding the earlier portion of his career, focusing mainly on his self-described expertise on the Constitution and his work as a historian of the Senate.  Only in this past year did media reports focus on his declining health and ability to serve, as Democrats finally removed Byrd as chair of Appropriations when it became clear that he wasn’t able to keep up with the task.

Our prayers are with the Byrd family and with the people of West Virginia.

Update: ABC News reports that the law in West Virginia says that the governor has to declare the seat vacant — and Manchin could wait to do that, apparently.  We’ll see whether West Virginians will demand immediate action.  However, the longer Manchin waits, the longer Harry Reid has to have one less vote for breaking filibusters, too.  I’m guessing that little will get done this week.

Update II: John McCormack has more thoughts.