Rep. Stephen F. Lynch swept to an easy victory yesterday for the state Senate seat vacated by William M. Bulger, ending a campaign that has already transformed South Boston politics.

With 65 of 66 precincts reporting, Lynch, a former ironworker and labor lawyer, polled 95.5 percent of the vote against his Republican opponent, Richard Czubinski, who received 3.6 percent of the vote.

With Lynch's victory a foregone conclusion, turnout was a mere 11.5 percent, although the district includes some of the most politically active neighborhoods in the city.