Updated 2:13 p.m. ET, Friday, 6/14
(CNN) - With Election Day in the special Senate contest in Massachusetts closing in, and the polls relatively tight, another top Democrat will make the trek to the Bay State next week to try and keep the long-held seat in party hands.
Biden will become the fourth top draw Democrat to stump for Markey in recent days. First lady Michelle Obama headlined a fundraiser for Markey in Massachusetts two weeks ago. President Barack Obama campaigned for Markey in the Boston area earlier this week, and former President Bill Clinton is scheduled to team up with Markey at a rally Saturday in Worcester.
The vice president's trip to Massachusetts next week follows a fundraiser he and former Vice President Al Gore held for Markey in Washington on Tuesday, while the candidate was at a debate in Massachusetts.
Republicans say the visits are a sign Democrats are nervous. Democrats disagree, but say they are taking nothing for granted.
Markey, a 20-term congressman representing the commonwealth's 5th Congressional District faces off June 25 against Republican Senate nominee Gabriel Gomez, a businessman and former Navy SEAL.
While Markey has consistently led his rival in polls, the two most recent non-partisan, live-operator surveys, released earlier this week, both indicated Markey with a narrow seven point advantage.
Last week, two national Democratic groups, the Democratic Senatorial Campaign Committee, which is the campaign arm of Senate Democrats, and the independent Senate Majority PAC, both went up with television commercials in support of Markey for the first time in the race. And Friday the Markey campaign went up with a new TV ad that consisted entirely of the president touting Markey at this week's rally. It ends with Obama saying "I need Ed Markey in the United States Senate." The campaign says the spot will run statewide.
National Republicans, who have not gone up with similar ads in support of Gomez, say that Democrats are nervous.
"The Markey machine is panicked, which is why Democrats are pouring millions of dollars and sending in their biggest names to try to revive Ed Markey," says National Republican Senatorial Committee Press Secretary Brad Dayspring. "In private, Democrats admit that Markey is a stale candidate whose campaign flatlined weeks ago. Actions speak louder than words, and the Democrats' actions depict a fear of a Gomez surge."
National Democrats push back against such talk.
"Democrats are extremely confident that Ed Markey will win this election, but we are taking nothing for granted. Top Democratic leaders indicated months ago that they planned to campaign for the nominee in this race," said DSCC Deputy Executive Director Matt Canter.
The two candidates have debated twice and have one final showdown next week. The winner of the special election will serve the remaining year and a half of the term of longtime Democratic Sen. John Kerry, who stepped down earlier this year to become U.S. secretary of state. The winner will also succeed William "Mo" Cowan. Democratic Gov. Deval Patrick appointed his former chief of staff to serve as interim senator after Kerry stepped down.
This is the second special Senate election in Massachusetts in the past three years. In January 2010, little known GOP state lawmaker Scott Brown pulled an upset over state Attorney General Martha Coakley in a contest to serve the remainder of the term of the late Democratic Sen. Edward Kennedy. (Brown lost re-election last November to Democrat Elizabeth Warren.)
While there are a lot of differences between the 2010 campaign and the current one, it appears Democrats are not taking any chances this time around.
"I don't think anyone thinks this is 2010. It doesn't feel at all like 2010. But those memories still haunt. So I think we're treating it like it's 2010, and doing everything we can to make sure 2010 doesn't happen again. I think we learned our lesson," says a Democratic operative who asked for anonymity to speak more freely.
Low turnout is expected for the special election, which could make things dicey for both campaigns.
"In a low-turnout, off-year special election, we can't take anything for granted. Low turnout is never our friend, even in a blue state. When turnout is higher, we do better. And I think bringing in two presidents, a vice president and a first lady can help engage and energize voters to make sure that they do turn out," says Mo Elleithee, a Democratic strategist, founder of a D.C.-based public affairs and political consulting firm, and veteran of numerous presidential and senate campaigns.