As voters prepare to head to the polls Tuesday, the US Senate candidates are scrambling to motivate a tiny fraction of the electorate, most of them core party activists they believe will turn out in a low-profile election, when most of the public’s attention is still riveted on the Marathon bombings and the ensuing investigation.
Edward J. Markey, the veteran congressman from Malden who is considered the front-runner for the Democratic nomination, is focused on liberal enclaves across the state as he faces a spirited challenge from US Representative Stephen F. Lynch, a centrist and former labor leader.
The two are engaged in a traditional Democratic Party fight that pits working- and middle-class voters against professional, suburban liberals. Lynch is looking to a strong turnout in more conservative, blue-collar Democratic communities, while Markey is counting heavily on his appeal to the progressive base that dominates party primaries.
In the Republican contest, the socially and fiscally conservative candidate, former prosecutor Michael J. Sullivan, is vying against two social moderates: Gabriel E. Gomez, a Cohasset businessman and former Navy SEAL, and two-term state Representative Daniel B. Winslow of Norfolk, a former district court judge.
While the GOP race will turn on who can pick up more of about 150,000 Republican votes expected to be cast in the primary, the Democratic contest may well hinge on whether Markey has been able to reassemble the formidable field organization that Elizabeth Warren’s Senate campaign and the Obama presidential team created in Massachusetts last year.
Markey’s campaign aides are convinced they have cobbled together the same sort of broad coalition that includes gays and lesbians, Hispanics, women, and college students along with a large swath of traditional Massachusetts Democratic voters. They say they will have targeted those groups with door knocking and phone calls to 500,000 voters by the primary.
Lynch, a former president of Ironworkers Local 7 in South Boston, is relying on trade unions to bring out his voters — “lunch-bucket Democrats” as his spokesman said last week. He is also making a strong pitch for urban Democrats by talking about issues such as street violence and his background growing up in the South Boston housing projects.
Union activists “are fired up,’’ said Francis X. Callahan Jr., president of Massachusetts Building Trades Council union.
Lynch, struggling to break through the avalanche of news on the bombings, has tried to close the gap between him and Markey with attacks on the Malden Democrat’s record on national security issues as Boston wrestled with the Patriots Day terrorist attack.
“There was a late attempt by Lynch to change messages and focus on security issues,’’ said Stephen Ansolabehere, a professor of government at Harvard. “But I think it is too late to change the dialogue between the two of them.”
Markey, who has far outpaced Lynch in fund-raising, has continued during the last week to focus on issues such as gun control and climate change that have gained him support from a host of local and national Democratic interests groups.
In the Republican primary, Sullivan — seen by some as the front-runner — is drawing strong support from the conservative wing of his party, particularly opponents of abortion and gay marriage, groups who often vote even in low-turnout elections. He has also picked up endorsements from GOP elected officials, including sheriffs in Essex, Plymouth, and Bristol counties, and members of the party’s small legislative caucus.
Winslow, a social liberal, has sought to appeal to the moderate and libertarian Republican voters who elected William F. Weld and other Republican governors during the past two decades.
But independents who were critical to Weld’s coalition can vote in either primary, making it harder for Winslow to consolidate that bloc. He also has to compete for moderates with Gomez, who has been endorsed by Weld and is casting himself as a fresh face for the GOP.
With Sullivan and Winslow strapped for cash, Gomez has used his wealth and fund-raising ties to the financial world to air statewide radio and TV ads, allowing him to gain some traction in the final days.
Sullivan has responded with mailings to potential GOP voters that attack Gomez on his request in January to Governor Deval Patrick to appoint him interim senator.
The issue is the highest hurdle Gomez faces in getting past the party primary. In that letter, he noted his support for President Obama in 2008 and his backing of Obama’s policies on immigration and gun control.
Still, one high-level GOP official who is not affiliated with any of the campaigns but did not want to be quoted by name, said the Gomez campaign is exuding a growing sense of confidence. “They seem to have hit their stride,’’ said the official.
On Monday morning, Winslow will begin airing his first ad of the campaign, 24 hours before the polls open.
The two primary winners will square off in a June 25 vote as part of the special election that began in late January. The winner will replace John F. Kerry, who left the seat he had held since 1985 after Obama appointed him Secretary of State.
With little enthusiasm for the race and the inability of candidates to generate voter enthusiasm, veteran analysts and political operatives in both parties say they are unwilling to make confident predictions.
“There is a very little interest or even recognition of this primary among Republicans.’’ said Rob Gray, a veteran GOP political operative. “It looks like a very low turnout, and that means anything can happen.’’
Election officials are not optimistic that the voter turnout will even come close to the primary that was held for the US Senate seat in December 2009.
About 680,000 voters cast ballots in that four-way Democratic contest, but not much more than 500,000 are expected this year. If GOP observers are correct, Republican turnout will fall far short of the 180,000 who showed up to vote for Scott Brown in his lightly contested race for the party nomination in 2009. Predictions run from 120,000 to 150,000 this year.
The difficulty the candidates have faced in trying to connect with voters in the aftermath of the bombings was evident over the weekend, as turnout was often light as candidates visited communities across the state.