Although Americans are used to Labor Day campaign kickoffs, this year’s back-to-back political conventions meant exposure to more than the usual number of partisan promises of a bright future and excoriation of the opposition.

So, while most of us who address the national conventions like to think our words will make all the difference for our party and the great American who is our nominee, in reality our speeches usually just blend into a kaleidoscope of impressions the public takes from the week’s events.

That is why, in my own convention speech, I tried to tap into a sentiment already established in the public mind. I talked about John McCain’s remarkable and heroic record as a POW. But I also talked about the John McCain that I got to know while sitting in the desk next to his on the floor of the U.S. Senate.

Citing any senator’s record, however impressive, may or may not electrify convention delegates. But it was my way of laying down a marker on behalf of a theory I have about both conventions and campaigns in general. Even amid a convention’s staged bedlam and overly hortatory speeches, voters do pick up information that develops into lasting impressions that count for something on Election Day.

The pundits and the political class sometimes underestimate the extent to which the public, in its subliminal but thorough way, collects data and makes informed electoral decisions. In a broader sense, voters carry into the polling booth this ultimate question about presidential candidates: “Who do I trust to make the right decision?”

Key issues for voters in this election will be freedom and national security, and here their impressions will be vivid: rogue nations with rapidly developing nuclear capabilities, nuclear-armed nations in volatile regions such as India and Pakistan, traditional nuclear powers such as Russia flexing their muscles and threatening the liberty and stability of those around them, and China building up its military in a way that suggests it wants to beat the United States in more than gold medals.

Here McCain makes his own vivid impression. His record shows that, early on, he understood the ominous intentions of Russia’s leaders, made the Iranian mullahs fear him and foresaw the need for a troop surge in Iraq, which, along with his own military service and longtime Armed Services Committee membership, add up to real national security experience.

By contrast, voters struggle with his opponent’s virtually nonexistent record on these issues. It comes down to a common sense decision that says: With national security traffic so heavy, this is not the moment to turn the car keys over to a teenage driver. Presidents don’t have time for drivers ed.

On the economy, voters have the same impression of McCain that I had on the Senate floor, where he fought plenty of fiscal battles. Some he lost. Some he won. Sometimes his colleagues liked him for it. Sometimes they most decidedly did not like him for it. Continued...