When were election dates aligned?

[Al Murray]

This winter I plodded through Michael Holt's 1000 page "Rise and Fall of the American Whig Party." I learned from that book that prior to the ACW states held elections on their own schedule, rather than in a November every two years as we do now. This contributed to the fall of the Whigs, as they could not form a coherent platform because every year there were a couple of state races with splits among the voters over state issues that kept the parties having to garner votes over local issues year after year. Does anyone know when elections were aligned to happen every two years in November? I asked a local professor of American History and his answer was "good question."