How do you determine the winner of a presidential debate?

In the case of the Sept. 26, 1960, debate between Republican candidate and Vice President Richard M. Nixon and Democratic candidate Sen. John F. Kennedy, the medium made the difference. And it all took place in Chicago.

The event was the first televised presidential debate in a general election, and it was held at what was then WBBM-TV studios, 630 N. McClurg Court. (In 2017 the Rehabilitation Institute of Chicago is opening a $550 million hospital at the site.)

People who watched on TV — and saw Nixon's sweaty face and gaunt appearance — thought Kennedy won the debate. Those who listened on radio thought Nixon won, according to pollsters cited in Tribune stories.

Regardless of who won the first of four debates that year, the Chicago debate profoundly altered American politics. It wasn't until 1976 that another pair of presidential candidates agreed to share a TV stage to debate.

Today's presidential candidates have learned how to harness the power of TV, but also social media and the reactions are fast and furious. Tonight, Republican Party candidate Donald Trump and Democratic Party candidate Hillary Clinton will meet at Hofstra University in Hempstead, N.Y., to debate for the first time.

Here's a look at how the presidential debates compare:

1960 (Chicago Tribune 1960) 2016 (AP photo)

Date

1960 Sept. 26, 1960 2016 Tonight's debate is the first of presidential debates scheduled through Oct. 19.

Location

(Charles Osgood / Chicago Tribune) 1960 The former WBBM-TV studios at 630 N. McClurg Court were demolished in 2009. (AP photo) 2016 Tonight's debate will take place at Hofstra University in Hempstead, N.Y. The next Clinton-Trump debate will be Oct. 9 at Washington University in St. Louis. The third presidential debate will be at University of Nevada at Las Vegas on Oct. 19.

Participants

(Chicago Tribune 1960) 1960 Republican Vice President Richard M. Nixon and Sen. John F. Kennedy, D-Mass. (AP photo) 2016 Republican Party candidate Donald Trump and Democratic Party candidate Hillary Clinton.

Moderator

(AP photo) 1960 CBS News host Howard K. Smith (AP photo) 2015 NBC News host Lester Holt

Format

1960 Eight-minute opening statements, question-and-answer session and three-minute closing statements. 2016 Two-minute answers to moderator's questions, candidates can then respond to each other. The moderator will use the balance of the time in the segment for a deeper discussion of the topic.

Duration

1960 59 minutes 2016 90 minutes 8 to 9:30 p.m. CST today

New technology

1960 First televised debate. 2016 Event will be livestreamed on Facebook and Twitter.

Topics covered

1960 Domestic issues, including farm surpluses, fiscal policy, schools, bipartisan support, Social Security, Communist activities in the U.S., and political experience. 2016 "America's Direction, Achieving Prosperity, (and) Securing America." Essentially, any topic is up for discussion tonight.

Ratings

1960 70 million viewers 2016 Our prediction: H-u-u-u-g-e.

Total debates

1960 4 2016 3

Sources: The American Presidency Project; Commission on Presidential Debates; Associated Press; Chicago Tribune archives; Fox News Channel; CNN; and GOP.

@ChiTribGraphics