Unlike most states, a successor to fill Sen. Edward M. Kennedy's seat in the Senate will be chosen through a special election, not by the governor.
Massachusetts law requires a special election for the seat no sooner than 145 days and no later than 160 days after a vacancy occurs. The law bans an interim appointee.
The law was changed in 2004, when Sen. John Kerry became the Democratic Party's presidential nominee and Republican Mitt Romney was the state's governor. Before the change, the governor would have appointed a replacement to serve until the next general election.
That would have created the opportunity for Romney to install a fellow Republican in office, a move that Democrats who control the state legislature sought to prevent.
Last week, Kennedy asked Massachusetts lawmakers to change state law to give Massachusetts' current governor, Deval Patrick, a fellow supporter of President Barack Obama, the ability to appoint an interim replacement to Kennedy's seat should Kennedy be unable to continue serving.
"It is vital for this Commonwealth to have two voices speaking for the needs of its citizens and two votes in the Senate during the approximately five months between a vacancy and an election," Kennedy said in a letter to Patrick.
Though Massachusetts is dominated by Democrats, a change in the law isn't a sure thing. Patrick, Senate President Therese Murray and House Speaker Robert DeLeo _ all Democrats _ gave no indication if they would support the change.
Any change could not happen immediately. Lawmakers are not expected to return to formal sessions until after Labor Day, Sept. 7.