The first time Illinois held a primary election on St. Patrick’s Day, the boys at McCauley’s Tavern on Chicago Avenue weren’t happy. McCauley’s was a bar that catered to Irish immigrants, and when a Tribune reporter stopped by the week before the 1970 primary, its tipplers made it clear they expected to celebrate on their patron saint’s feast day.

“It’s a rotten conspiracy,” one man grumbled.

“Things will work out, just you wait and see, even if it is the first time that election day has fallen on the good saint’s day and they’ve moved the parade and everything,” said his friend.

“We’ll show them,” the first man vowed. “We’ll vote, and we’ll have our St. Paddy’s Day, too. On Tuesday.”

Why the conflict between voting and St. Paddy’s Day? In 1970, the Illinois primary — which included congressional and legislative elections — was moved from June to the third Tuesday in March. Legend has it this was a ploy by the Chicago Machine to make life difficult for independent challengers by forcing them to campaign throughout the winter.

In 1970, the third Tuesday in March was the 17th — St. Patrick’s Day, the biggest drinking day of the year. But there was another Illinois law, dating back to the Prohibition Era, which declared that “[n]o spirituous malt, vinous or intoxicating liquor shall be sold or given away at retail, nor shall any saloon or bar room or place where such liquor is sold or given away be open on any general or special election within one mile of the place of holding an election.”

That might not have been a problem for a downstate roadhouse, miles away from the township hall, but in Chicago, nearly every tavern and liquor store was within a mile of a voting booth, so they all had to close on election days. In the early 20th century, this law was taken so seriously that the Chicago Law and Order League pressured the city to shutter saloons caught serving booze during a primary and even arrest the proprietors.

The law was intended to fight election fraud by preventing politicians from trading drinks for votes. Of course, politicians found a way to do that anyway. The drinking ban inspired the famous Chicago tradition of precinct captains luring boozehounds to the polls with bottles of muscatel, since that was the only way they could get a drink on Election Day.

Once legislators realized their new primary date had ruined St. Patrick’s Day, they made a change — not to the primary, but to the law, repealing it in 1972. As the Tribune reported on April 27 of that year:

“The legislature has passed and Gov. Ogilvie is expected to sign a measure permitting saloons and liquor stores to stay open on election day. The measure repeals a dusty old law aimed at preventing unscrupulous politicians from buying votes with free drinks. As apparently occurred to the lawmakers, the old law was pretty unworkable. A bottle of booze is worth more votes when the taverns are closed than when they are open.”

Plenty of other states maintained their Election Day blue laws longer than Illinois. Indiana didn’t vote to allow drinking and voting until 2010. South Carolina, the last holdout, waited until 2014. But neither of those states ever held an election on St. Patrick’s Day.