As Republicans and conservatives zero in on the identity of the mysterious Internet visitor who coaxed an aide to Gov. Robert L. Ehrlich Jr. into spreading rumors about Baltimore Mayor Martin O'Malley, a question is blossoming in political circles. Does the identity of MD4Bush, the surreptitious user of a conservative Web site, matter? If revealed, will the knowledge change the public's perception of O'Malley or Ehrlich? Some political experts say that the answer to both questions is yes and that it's worth following the plot turns in the increasingly convoluted saga. If MD4Bush turns out to be a Democratic Party...