Russian social democrats are to hold their unification congress in Moscow Saturday. Plans are in place to establish a united political party on the basis of the United Russian Social Democratic Party, which is headed by former USSR president Mikhail Gorbachev, and the Russian Social Democracy Party. The latter is headed by Samara governor Konstantin Titov. (The city of Samara is located in the Volga region -- Ed.) The new party will also comprise a number of people siding with the Socialist Party and some other organizations. Experts estimate that the emergent party will have more than 30,000 members. Moreover, the constituent congress will approve the party's program and rules, also electing its governing bodies. Mikhail Gorbachev is expected to head this united party.