(CNN) – Rep. Ed Markey still leads his Republican rival in the battle for Massachusetts' open Senate seat, according to a poll released Monday, though his margin has shrunk in the final weeks of the campaign.
The Suffolk University survey showed Markey, a longtime Democratic congressman from the Bay State, ahead of Gabriel Gomez 48%-41%. Gomez is a businessman and former Navy SEAL. Previous polls have consistently given Markey the edge, including a seventeen-point advantage in one poll from early May.
Other surveys have shown a much tighter contest. In Suffolk's poll, voters said they were paying close attention to the slate of controversies currently facing President Barack Obama – a fact the pollster attributed to the narrowing of Markey's lead.
"Ed Markey continues to lead but the margin has dwindled," David Paleologos, director of the Suffolk University Political Research Center, wrote in a statement. "Markey's core ballot test number has fallen below 50 percent and recent Obama administration scandals, especially the Associated Press phone records scrutiny, have touched a nerve with likely voters who are holding back or no longer supporting Markey and President Obama with the same intensity."
Massachusetts voters will choose a new U.S. senator in a June 25 special election. The winner will finish the remainder of former Sen. John Kerry's term. Kerry left Congress after becoming secretary of state.
The race has been marked by bitter sparring between the two rivals. Markey has cast newcomer Gomez as a partisan Republican, including in the pair's first debate held last week when he called Gomez "the same old stale" type of Republican that lost last year's presidential race.
For his part, Gomez has equated his Democratic rival to "pond scum" for a web video that pictured him on screen with Osama bin Laden.
In Monday's poll, voters were questioned about the two rivals' claims – with neither gaining much traction.
Only 13% said they agreed with Gomez's "pond scum" charge, while 21% said they believed Markey when he characterizes Gomez as a tool of the "extreme right wing."
The Suffolk poll was conducted by telephone June 6-9 from 500 likely voters. The sampling error was plus or minus 4.4 percentage points.
CNN's Kevin Liptak and Paul Steinhauser contributed to this report.