Conventions as we know them today — major events held in large cities attended by party insiders — began in the early- to mid-1800s. State parties needed to coordinate their activities and nominate someone who would appear on the ballot across the country, explained University of Wisconsin-Madison political science professor Barry Burden.
“All that changed 50 years ago, when the parties changed their nomination systems to emphasize primaries and caucuses as the ways that delegates would be selected,” Burden said.