BOSTON (CNN) -- U.S. Rep. Ed Markey will win Tuesday's special U.S. Senate election in Massachusetts and serve the remainder of fellow Democrat John Kerry's term, CNN projects.
Markey defeated GOP businessman and former Navy SEAL Gabriel Gomez.
The Democrats' majority coalition in the Senate remains 54-46.
Markey will serve Kerry's remaining year-and-a-half term. He can seek re-election for a full six-year term in 2014.
Kerry stepped down earlier this year to succeed Hillary Clinton as Secretary of State.
Markey, who has served 20 terms in the U.S. House, was consistently on top of Gomez in public opinion polls, including a 10-point, 52%-42% lead in a Suffolk University survey of likely voters released Monday and a 49%-41% advantage in a Western New England University poll released Sunday.
The race was marked by its nastiness, with both candidates leveling charges of hyper-partisanship to try and sway voters in the Bay State.
Markey demanded Gomez release more of his income tax returns to shed light on a real estate transaction. Gomez suggested Markey wasn't a valid resident of Massachusetts after three decades in Washington.
Gomez called Markey "pond scum" for airing an ad that pictured him alongside Osama bin Laden. And Markey cast doubt on Gomez's past as a private equity investor since Gomez wouldn't disclose his list of clients.
Markey succeeds William "Mo" Cowan. Democratic Gov. Deval Patrick appointed his former chief of staff to serve as interim senator after Kerry stepped down.