(CNN) – A day ahead of the first debate between U.S. Senate candidates in Massachusetts, a new survey shows Democratic Rep. Ed Markey leading rival Gabriel Gomez by double digits.
The poll, released Tuesday by New England College, showed 52% of registered voters in the Bay State support Markey, who's serving his twentieth term in the U.S. House as the representative of Massachusetts' 5th Congressional District.
Gomez, a private equity investor and former Navy SEAL, was at 40% in the survey. Another 8% said they were still unsure of who they'll support in the June 25th special election.
While both candidates enjoyed similar levels of support among their parties – Markey was at 75% among Democrats, and Gomez at 76% among Republicans – the higher number of Democrats in Massachusetts gave Markey his edge.
"The overwhelming Democratic registration edge and Markey's strong support among Democrats mean that Gomez has a big hill to climb to be competitive in this race," said Ben Tafoya, the director of the New England College Polling Center.
Both candidates held 52% favorable ratings, thought a greater number – 22% - said they were unsure of Gomez, who hasn't held public office in the state.
Polling in Massachusetts has consistently given Markey the edge, though the margins have varied. A 7 News/Suffolk University survey from early May gave Markey a seventeen-point advantage, while other poll showed a much tighter contest.
Markey and Gomez will meet for their first debate Wednesday in Boston, setting off the final month of campaigning for the seat that opened up after John Kerry left to become secretary of state. President Barack Obama will head to the state next Wednesday to campaign for Markey, a White House official and Markey campaign official both said.
The New England College poll was conducted by telephone June 1-2 from 734 registered voters. The sampling error was plus or minus 3.62 percentage points.