"The Gomez campaign is surging and defying conventional wisdom because he's appealing to independents, getting his message out and outworking career politician Ed Markey," Ritter said. "Ed Markey, absent from both the campaign trail and Congress, is hoping outside groups and negative ads will deliver him the seat he feels he's entitled to."
The Gomez aide tried to tamp down expectations for the debate, but said "we are going to make this race a referendum on Washington, we are doing everything we a can to tie Ed Markey to the scandals in Washington, to the dysfunction."
As for Gomez's attempt to distance himself from the national party, his aide said their opponent is "desperate" for the race to be "Barack Obama against George W. Bush" and to portray him as a "crazy right-wing nut" and Markey wants to "pretend he is Barack Obama or Elizabeth Warren."
"Anything but Markey vs. Gomez because he knows he has a pretty good chance of losing if it is Markey vs. Gomez," the aide said.
Massachusetts GOP committeeman Ron Kaufman noted that the debate has some competition tonight because the Boston Bruins face off against the Pittsburgh Penguins in Game Three of NHL Eastern Conference finals.
"I'd be shocked if the viewership is particularly high," Kaufman said. "Having said that, it's a good opportunity for Gabriel [Gomez] to get to know the voters and vice versa. I think he will do well and it's a good chance for him."
The Markey campaign counters Gomez's argument, saying fundraising by Republicans like Rubio of Florida and McConnell of Kentucky shows he has the "full throated support of right-wing Republicans" in their effort to "control the Senate."
Markey spokesman Andrew Zucker said Gomez will "enact a right-wing agenda that hurts Massachusetts families," noting his policy stances on abortion and gun control.
"There is no hiding or disguising those facts from the people of Massachusetts," Zucker said.
Gomez has said he is "personally pro-life," but won't attempt to change abortion law, calling Roe vs. Wade "settled law," in an interview with the Boston Globe. He accepts exemptions like rape, incest or danger to the life of the mother.
On gun control, he does not support bans on assault weapons and high-capacity magazines, calling them ineffective. He has called for expanded background checks.
Markey, 66, is trying to become a U.S. senator at a time when Congress is wildly unpopular and he has represented his Massachusetts district in Congress for 36 years. Unlike the rest of the country, however, Congress is not as unpopular in the Bay State as it is nationally and people like the president and Sen. Elizabeth Warren, D-Mass., remain popular.
But the president's visit "does represent a bit of nervousness on the part of Democrats," Tufts professor Berry said, noting that he should raise even more than the $600,000 his wife raised when she fundraised for Markey last week.
"Obama is coming primarily to raise money for Markey rather than reassuring Democrats."
Berry added that "at this point in the  Coakley-Brown race, Brown was showing momentum" and he does not see that "at this point" for Gomez. Scott Brown upset Martha Coakley to take the seat that had been held by Ted Kennedy.
The Cook Political Report did move the race last week to a toss-up and Jennifer Duffy, who moved the race, said "special elections are quirky things."
"Do I have more faith in the Democratic candidate turning out their voters? Yes, because they've proven it time and time again," Duffy said, adding that "Gomez has got to get on the air, put more points up and they have to be all bio ads."