BOSTON (AP) -- Massachusetts Republican Scott Brown, whose surprise win in the race to fill the late Sen. Edward M. Kennedy's seat created the sonic boom heard all the way to Washington, was visiting the nation's capital Thursday to pay a round of courtesy calls on his new colleagues.

Two days after his win cost President Barack Obama his filibuster-proof 60-vote majority in the Senate, Brown was making his first trip to the institution he reordered and the city he set abuzz after Tuesday's upset election.

The timing of his swearing-in remained in question. While Massachusetts Secretary of State William Galvin sent a letter to the Senate clerk Wednesday declaring Brown the unofficial winner of the seat, senators had to decide whether they were going to waive a waiting period for absentee ballot arrivals...