Now in the final hours, the campaigns for control of suburban courthouses have arrived with signs sprouting at intersections and highway on-ramps, TV attack ads complete with scary music, and last-minute hit pieces in mailboxes.

On Tuesday, voters will determine whether Democrats can finally win significant county-level power by capitalizing on their growing number of registered voters, leftward trends in presidential and congressional elections, and public dissatisfaction with the Bush White House and the Iraq war.

“The Democrats are poised, but their real challenge is going to be turnout,” said Larry Ceisler, a Democratic media consultant who is not working in any of the races. “The question is: Can the Democrats get the voter who votes for the party’s candidates . . . for president and Senate to come out in a local election?”