Boston ? Massachusetts’s top election official says it could take weeks to certify the results of the upcoming U.S. Senate special election. That delay could let President Barack Obama preserve a key 60th vote for his health care overhaul even if the Republican who has vowed to kill it wins Democrat Edward M. Kennedy’s former seat.

Secretary of State William F. Galvin, citing state law, says city and town clerks must wait at least 10 days for absentee ballots to arrive before they certify the results of the Jan. 19 election. They then have five more days to file the returns with his office.