Cambridge Mayor Thomas W. Danehy is not a happy man.

He is trying to fill a prescription in the drugstore that he manages up Mass Ave. But there is a problem. Some constituent is on the phone with the mayor/druggist, complaining about the cockroaches in her building "so big that you could saddle them," and about the planes that have been rerouted over Cambridge. Danehy does not look well.

But for the mayor of Cambridge--who has been in office for about 15 months now--this day is relatively slow.

A 12-year veteran of the City Council and no babe-in-the-woods to the strange brand of incest and threat that is Cambridge politics, Danehy has seen worse times come and go.

Relations between Harvard and the city, Danehy explains, are "like a menstrual cycle--it goes over and over and over again." What other councilors have labelled a rapid deterioration in recent months is nothing new, he says.

Danchy explains away the recent vote in the City Council to set a height limit on new buildings constructed in Harvard Square. "We're in the odd year," he says. Odd years mean City Council elections in Cambridge, he warns--and then just smiles.

While Danchy says he sympathizes with the residents and officials who talk about the aesthetic value of Harvard Square and the tradition and all that," at heart he is still a very pragmatic politician.

His philosophy is simple. "If you're going to go for something anything--and you don't have the votes, you don't go for it," he says.

Danchy warns that the City Council may be tying its own hands by restricting building heights in the square. There's only six square miles in Cambridge that can be commercially developed, he says--but you can't count the two-plus owned by Universities.

"If you're going to expand your tax base," Danehy says, "and you've only got three and a half square miles in which to do it, you're going to have to go up."

Danchy's real worry, however, is not battling his fellow councilors or Harvard officials, but matching blow for blow with the Massachusetts Bay Transit Authority (MBTA), the agency that wants to extend the Red Line through Harvard Square. As he speaks of it, his manners change and his eyes light up.

"We already have an adequate surface transportation system in Cambridge," Danehy says for the hundreth time in as many days. The MBTA's chosen route is wrong, their methods of construction are wrong and their effect on Cambridge is wrong, he adds.

So wrong in fact, that Danehy cajoled and argued and pressured the City Council to join in a citizen group's suit asking for an injunction against the MBTA's construction activities.

Danchy offers no excuses. "Everything you try to do in Cambridge winds up in court," he says.

To make matters worse, what the mayor sees as a conspiracy to extend the Red Line and drown out mass community opposition is gathering steam. Legislation introduced in the Massachusetts House--H.R. 1921--could effectively nullify the city's voice in the extension process. "If that passes, it will be disastrous," Danehy says.

But fighting that disaster would be nothing new for the mayor of Cambridge.