Editor's note: CNN Contributor Bob Greene is a best-selling author whose 25 books include "Late Edition: A Love Story"; "Duty: A Father, His Son, and the Man Who Won the War"; and "Once Upon a Town: The Miracle of the North Platte Canteen."
(CNN) -- "To report the state of the union."
Within the first few seconds of President Barack Obama's address Tuesday night, he quoted the late President John F. Kennedy, who 51 years ago used those words to describe a president's annual duty.
As Obama spoke, citizens around the country were tapping away at keyboards, posting and sending messages -- public and private -- characterizing their own view of how the union, and its president, are faring.
Obama told the packed House of Representatives chamber:
"We can say with renewed confidence that the state of our union is stronger."
And those citizens around the country, typing away, were in essence saying:
We'll be the ones to decide that, thank you very much.
It is one of the most profound changes a modern president faces: The fact that the day is long gone when a chief executive can declare what the status of the nation is and have the words be treated as a one-directional proclamation rather than as the first salvo in an instant conversation. Twitter reported that as Obama discussed the middle class and minimum wages, its users were posting messages at the rate of 24,000 per minute.
The State of the Union address, for more than a century -- from Thomas Jefferson to Woodrow Wilson -- was not even delivered verbally to Congress.
It was handed to the House and Senate on paper, and then printed -- usually in full -- in newspapers across the country. Americans studied the words as they would a major company's annual report. The official version -- the hot-off-the-presses results of the nation's yearly physical exam.
The dynamic, of necessity, has been forever altered.
"I'm also issuing a new goal for America," Obama said Tuesday night, and before he could even complete the sentence, he had to know that there were plenty of people who would automatically reject whatever words would follow and would not be shy about it.
Self-doubt is a characteristic that a modern president of either party must banish as he speaks. If he were to dwell on the fact that every single syllable he utters is being dissected in real time, it would be understandable if he were unable to make it through a paragraph.
"We know what needs to be done," Obama said, but that word -- "we" -- is itself open to daily dispute. A president's voice may be, symbolically, the loudest in the republic, but it is one voice among hundreds of millions, most of them with the technological power to talk right back. Democracy, at warp speed.
Slaughter: Obama dares Congress to get the job done
That endless and instantaneous conversation -- and it is only going to grow more constant in the decades to come -- is the contemporary reality to which each president must now adjust, the fresh fact of civic life. It is, in a fundamental way, the new state of the union.
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The opinions expressed in this commentary are solely those of Bob Greene.