Turnout will be key for Tuesday's special election to fill the late Sen. Edward M. Kennedy's seat. Republican Scott Brown and Democrat Martha Coakley crisscross the state for support. In the final moments of a U.S. Senate race that was never expected to be close, Republican Scott Brown and Democrat Martha Coakley crisscrossed Massachusetts on Monday, a day before an election that could alter the fortunes of both major political parties.