US Representative Michael E. Capuano has decided to pass up a run for the US Senate, removing a huge hurdle for his Democratic colleague Edward J. Markey, the dean of the state’s congressional delegation, who has been trying to empty the field for the party’s primary, analysts say.
Capuano’s move also puts pressure on the other only major potential contender in his party, US Representative Stephen F. Lynch, a South Boston Democrat who confirmed Tuesday that he is still taking a hard look at running in the special election to fill John F. Kerry’s seat.
“I have not made a final decision,’’ Lynch said shortly after Capuano’s announcement. The congressman said he will continue to explore the potential for a campaign over the next several weeks.
But Lynch and several analysts agreed that Capuano’s absence from a race will make it harder for Lynch to successfully challenge Markey, who will probably be a more attractive candidate to the liberal base.
Markey, who quickly jumped into the campaign several weeks ago, has already locked up Kerry’s support and received the backing of the Democratic Senatorial Campaign Committee and of Victoria Kennedy, the widow of Edward M. Kennedy.
“It is absolutely more difficult in a smaller field,’’ said Lynch, whose more conservative positions puts him at odds with liberal voters. He said he agreed with the analysis that his candidacy would better in a crowded primary.
“That is the popular wisdom, and it is probably correct,’’ said Lynch. “But it won’t determine the outcome of my decision.’’
The lawmaker, a former ironworker, has tried to muster union support for his cause, arguing that he would bring a blue-collar perspective to the clubby Senate. His strategy to win a Democratic primary would be aimed at drawing conservative Democrats and independents to the polls.
President Obama has nominated Kerry for secretary of state, and the Senate is expected to confirm him before the end of the month. A special election would probably be held June 18, according to state election officials, with a primary taking place at the end of April.
Michael Shea, a Democratic media consultant who has worked for Capuano’s campaigns over the years, said the prospect of facing Markey in a one-on-one race now has to be a factor in his decision making.
“The ideal field for Lynch is a half dozen liberals dividing up the vote,’’ said Shea.
In addition to his strong endorsements, the 66-year-old Markey is sitting on a hefty $3.1 million campaign account. But he has yet to convince many party loyalists that he is a strong enough candidate to beat former Senator Scott Brown if Brown decides he wants to run again.
Despite building a strong reputation in Washington for his leadership on telecommunications, energy, and environmental issues, Markey is largely untested as a candidate, having avoided difficult campaign challengers since being elected to Congress 36 years ago.
Capuano, the former mayor of Somerville, said in a one-paragraph statement Tuesday said he looks forward to “focusing on the important issues facing the new Congress” and called his work in the House “the greatest honor of my life.”
Markey called Capuano “a powerful and highly respected member of Congress.’’