A few California Democrats found out what happens when you don't toe the line.

Senate President Pro Tem Don Perata flashed a show of power Monday by locking three moderate Democratic senators out of their offices after they attended a fundraiser last week.

The Oakland Democrat apparently was irked that the three Southern California lawmakers, Sens. Ron Calderon, Gloria Negrete-McLeod and Lou Correa, attended a dinner in Sacramento held by pro-business Assembly Democrats who call themselves the ''Mod Squad.''

Senate Democrats have an unwritten rule forbidding members from joining caucuses except those reflecting gender, geography or ethnicity -- such as the Latino or rural caucuses -- mostly as a way to keep lawmakers from forming voting blocs that could hinder the party's agenda.