THE ELECTION OF City Councilor Thomas W. Danehy as Cambridge's new mayor is a disappointment but it probably will not change the progressive orientation of Cambridge's administration. Under the city's form of government the office entails much more pomp and circumstance than actual power.

The council still remains split four to four, along progressive-conservative lines with the unpredictable Alfred E. Vellucci providing the swing vote. Vellucci's vote for Danehy appears to be a petulant, isolated one, spiting the progressive coalition which elected him mayor in 1975 and supported him in the most recent election. But if his support for Danehy results in Vellucci sliding into the conservative camp, this somewhat Faustian pact will have severe repercussions.

The mayor also serves as the chairman of the School Committee, which is divided three to three between independents and members of the Cambridge Convention slate. It is still unclear as to what the committee's major issues and voting coalitions will be and so the impact of Danehy, Roman Hruska's ideological twin, remains uncertain.