"The United States Senate is the judge of the qualifications of its own members," Galvin told CNN's Rick Sanchez. "In other words, they get to decide who is seated and when. "
Sen. Paul Kirk, who was appointed by the state's governor to be the interim replacement for the late Sen. Ted Kennedy, will serve until the Senate decides to swear in either Martha Coakley, a Democrat, or Scott Brown, a Republican.
"Senator Kirk will serve until his successor has qualified, that means sworn in," Galvin said.
Though the ultimate decision rests with the Senate, Galvin also said Tuesday that if the results of Tuesday's voting are decisive, he will announce those unofficial results as soon as he can.
"A decisive result would be one that would be beyond the margin for a recount, which would be one half of one percent," Gavin said. "I would also want to make sure that it was outside the margin of uncounted absentee ballots."
Galvin said he is obligated under federal law to make sure that overseas absentee ballots from U.S. service members are counted. "If they could affect the outcome, then you could not issue such a letter" declaring a winner based on unofficial results, he said. Federal law requires 10 days after election day to wait for overseas absentee ballots, Galvin explained.
If the results are not decisive, then Galvin said a recount was possible. In the event of a close result, he said, "we have to make sure that every ballot that has been submitted is counted. That is to say the overseas absentees. It also opens opportunity for one of the candidates or both of them perhaps to request a formal recount."
Galvin added that if a recount does occur, a hand count of the paper ballots would be possible.
"If the result is not decisive, then it's important that . . . the result is accurate and complete," he said. "And I'm committed to seeing that it's accurate and complete. We do not rush to judgment in Massachusetts at the expense of voters' rights. We regard the voters' rights as the highest rights."
"Whatever the voters' decision, it will be honored," he said. "It's my job to see that decision is given effect."