House Speaker Robert DeLeo, a Democrat, said the change is needed to ensure Massachusetts continues to be represented by two senators until voters can choose a replacement during a Jan. 19 special election.
"I just want to make sure that Massachusetts has a say ... that Massachusetts has their voice heard on health care, on the environment, on clean energy," DeLeo said.
Patrick, a Democrat and ally of President Barack Obama, also supports the change. Republicans, who number just 16 in the House, oppose the bill.
They point out that Democrats changed the succession law in 2004 to create a special election and block then-Gov. Mitt Romney, a Republican, from naming a temporary replacement if Sen. John Kerry had won his presidential bid.
To change the law now that there is a Democrat in the governor's office smacks of hypocrisy, they said.
"When Senator Kennedy passed away we started (with) the law that was on the books and we shouldn't be changing the law midstream," said House Republican leader Rep. Bradley H. Jones Jr. "Everything else is ancillary and extraneous to that."
Kennedy died of brain cancer on Aug. 25.
Rep. Michael Moran, House chairman of the Committee on Election Laws, said lawmakers shouldn't be handcuffed by past votes if they are not in the best interest of the state.
"I ask you to focus on the needs of Massachusetts not in 2004, but in 2009," the Boston Democrat said.
Other Democratic lawmakers conceded a political motive in the vote, saying they wanted to protect Kennedy's legacy, including his signature issue of expanded health care.
"Some people say it's political. Of course it's political," said Rep. Cory Atkins, a Concord Democrat and Kennedy supporter.
The bill initially would have required the appointee be from the same party as the person who created the vacancy, a Democrat in the case of Kennedy's successor.
That requirement was stripped after critics raised constitutional concerns and noted that more than half of voters in Massachusetts aren't enrolled in any party and would be barred from consideration.
Kennedy, in a letter sent to lawmakers before his death, urged the change in law saying "it is vital for this Commonwealth to have two voices speaking for the needs of its citizens."
The debate is being followed closely in Washington, where Democrats hope to regain a 60-vote, filibuster-proof margin in the U.S. Senate ahead of any debate on President Obama's health care overhaul.
Massachusetts Sen. John Kerry, Senate Democratic Leader Harry Reid of Nevada and Massachusetts' all-Democratic delegation to the U.S. House also back the change, saying they need all the votes they can to support the health care change.
Obama presidential counselor David Axelrod has contacted Massachusetts officials, according to White House Press Secretary Robert Gibbs. The Massachusetts branch of Obama's political arm, Organizing for America, has sent out e-mails advocating for the change.
DeLeo said lawmakers wanted to bar any appointee from also running as a candidate in the special election, but said they could not constitutionally include that provision in the bill.
DeLeo said House lawmakers instead hoped to pass a separate resolution stating that it is the intention of the House that an appointee not also be a candidate in the special election.
Patrick has said he would extract from the appointee a promise not to be a candidate in the special election.
The bill was immediately shipped to the Massachusetts Senate. Senate President Therese Murray, a Democrat, has been tightlipped about the bill's chances in that chamber.
Senate Republican leader Richard Tisei has said he'll object to the Senate taking up the bill. Senate rules require unanimous consent to debate a bill not already on the calendar, and the succession bill wasn't listed for Thursday's session.
An objection would delay it until the Senate's next formal session. There is none scheduled for Friday. Tisei could use other parliamentary moves to delay a vote for additional days.
Those said to be under consideration for an interim appointment include former Gov. Michael Dukakis, former Democratic National Committee Chairman Paul Kirk Jr.; former Massachusetts Senate President Robert Travaglini, former Kennedy staff chief Nick Littlefield, Harvard Law School Professor Charles Ogletree and former state Treasurer Shannon O'Brien.
Candidates seeking the Democratic nomination in the special election include Attorney General Martha Coakley, U.S. Rep. Michael Capuano and Boston Celtics co-owner Stephen Pagliuca. State Sen. Scott Brown and Canton Selectman Bob Burr are seeking the Republican nomination.