It is generally agreed that Maaser (i.e. Charity) may not be used to cover
an obligation (on the other hand, when the means to fulfill a mitzvah from
any other source are lacking many authorities permit the use of Maaser). In
the past Jewish communities were more independent and self-governing, and
communal commitments were less voluntary in nature. As a result most
synagogue donations are used for essential communal needs like salaries,
lighting, etc., and Maaser money was not to be used. Only the proportion of
the synagogue donation corresponding to the proportion used for the poor
could have been taken from Maaser funds.
Today there is a greater leniency of recent authorities because Jewish
communities are not independent and self-governing and communal commitments
are more voluntary in nature (Rabbi S.Z. Auerbach).
Roger
(See my page http://www.carasso.com/roger/charity.html)
roger@carasso.com