After several months of battling for the Suffolk-Middlesex State Senate seat, incumbent Michael LoPresti '70 and Boston City Councillor Robert Travaglini face the voters Thursday.

LoPresti has based his campaign on his 15-year record of achievement in the State Senate and has garnered the endorsements of several liberal groups and most of Cambridge's elected officials.

Saying that the region needs a "full-time" state senator, Travaglini and his supporters have charged that LoPresti spends too much time in his job as a private attorney to be an effective representative, that he is inaccessible to the average voter and that he too often acts to please lobbyists at the expense of constituents.

While he won his first election on promises to respond to voter needs, "somewhere along the line, [LoPresti] lost that commitment" to accessibility, Travaglini's campaign manager, Carmen Monks, said.

"It's an issue of full-time representation. [LoPresti's] a full-time attorney, [while] Bob is a full-time politician. $48,000 or $50,000 is a full-time job and should be taken as such," Monks said.

But members of the Cambridge City Council, eight of whose nine members have publicly endorsed LoPresti, say that he is an effective representative of his constituents and believe there is no reason to replace the sixth highest ranking member of the State Senate. The ninth member, David E. Sullivan, serves as general counsel to the Secretary of State and may not legally make endorsements.

"Every time I ever called the man for a constituent, he has responded," said City Councillor William H. Walsh. "My experience with him has been very positive."

"A good representative doesn't have to be somebody who sits in an office all day," Walsh said. "The fact that he sits in another job, as an attorney, so what?"

Cambridge City Councillor and former Mayor Walter J. Sullivan Jr., called Travaglini a "nice kid" but added that "we've had good representation with Michael [LoPresti] in there, and you don't change a horse in the middle of the stream."

Walsh and other LoPresti supporters have also called Travaglini a cynical opportunist who has changed his views on a number of major issues and has suddenly gone over to the liberal side to sway voters.

"Clearly, he's voted one way on some issues and now changed his position," Walsh said. "My impression is that if [Boston Mayor] Ray Flynn told him to jump off a building, he'd do it, and I think that's not good leadership."

LoPresti and his backers have also castigated Travaglini for supporting an increase in property taxes that were capped tightly by Proposition 2-1/2 in 1980. LoPresti's largest campaign advertisement blares that "Proposition 41/2," which Travaglini supports, would double taxes in the region.

"That's just an example of Mike taking a statement out of context," Monks said. "No way are we advocating a tax increase."

However, despite the endorsements which LoPresti has received from city councillors and community activists, not everyone believes that LoPresti is as liberal as he describes himself.

Marguerite Gerstell, a lesbian candidate who dropped out in July after LoPresti received the endorsement of the Greater Boston Lesbian and Gay Alliance, called LoPresti a political opportunist in a letter to the editor of the Cambridge Tab last week.