Senator Edward Kennedy has made healthcare a signature issue
US Senator Edward Kennedy has asked the Massachusetts governor to change state law to allow a speedy succession when his seat becomes vacant.
The 77-year-old Democrat was diagnosed with a malignant brain tumour in May.
In his letter, Mr Kennedy asks that the state appoint someone temporarily to bridge the gap before voters choose a new senator in a special election.
It is believed Mr Kennedy wishes to ensure that the US president's healthcare bill is passed.
Throughout his life, healthcare has been a signature issue for the senator; President Barack Obama has said he has done more to advance the issue in the US than anyone else.
In the letter, obtained by The Boston Globe newspaper, Mr Kennedy writes: "It is vital for this commonwealth to have two voices speaking for the needs of its citizens and two votes in the Senate".
EDWARD MOORE KENNEDY
1932 Born, youngest of nine children
1962 Becomes country's youngest senator
1963, 1968 Brothers President John F Kennedy and Senator Robert F Kennedy both assassinated
1969 "Chappaquiddick incident" - Kennedy flees scene after road crash in which his young passenger dies
1980 Runs unsuccessfully for Democratic nomination against sitting President Jimmy Carter
Under current law, if a senator dies or steps down, voters must chose a replacement in a special election held within five months.
But Mr Kennedy, analysts suggest, fears a lengthy gap could deny Democrats a crucial vote on the proposed health reform.
Although the letter was sent this week, the senator's aides insist that there has been no deterioration in his condition.
"For almost 47 years, I have had the privilege of representing the people of Massachusetts in the US Senate," Mr Kennedy writes.
He said being a senator: "has been - and still is - the greatest honour of my public life".
The youngest brother of assassinated President John F Kennedy, he is one of the best-known Democratic politicians and the second longest-serving member of the Senate.
He was first elected senator for Massachusetts in November 1962 - shortly after turning the requisite 30 years of age - to replace his brother, who had been elected president in 1960.
Since then he has been re-elected seven times.