Trump's behavior is 'unprecedented'? Check your history

• Collusion or no collusion, President Donald Trump's amateurish behavior is relatively obvious.
• Yet voters have devalued professional conduct and political experience for 25 years.
• Each of the last four presidents have been less traditionally qualified than their original general election opponents.

Saul Loeb | AFP | Getty Images

President Donald Trump waves to wellwishers as he arrives at the 72nd US Women's Open Golf Championship at Trump National Golf Course in Bedminster, New Jersey, July 16, 2017.

Once again, America is pretty much split down the middle over a political controversy. Democrats and the Left in general are obsessing over continued allegations of Russian collusion with President Donald Trump's 2016 campaign.

Republicans, and the Right in general, are pooh-poohing the whole thing. That kind of partisan split over a scandal or alleged scandal is nothing new.

Still, there is more general agreement that the Trump team has been sloppy and less professional that it should be, in everything from its communications operation to how it's handled its hiring. President Trump is the source of most of this criticism, as he continues to communicate with the public in a casual and often reckless way on Twitter, and even on camera.

Actually, a lot of Americans find the unrehearsed and clumsy veneer of the Trump administration to be refreshing. It's obvious that a lot of voters preferred a sloppy yet more genuine candidate like Trump, who contrasts sharply with the very tight and packaged Hillary Clinton. It just seems more real, and in an image-dominated field like politics, that's a big deal.

But the Trump amateurishness is really just the latest example of a massive sea change in Republican and Democrat voter attitudes that previous generations could never have fathomed. The simple fact is that Americans have abandoned the idea of wanting an experienced hand to be their president, or at least making that a prerequisite for the office. And the proof is in the results of every presidential election since 1992.

Most are probably too partisan to digest the following sentence calmly and fairly, but here goes: U.S. voters have elected four non-qualified presidents in a row.

By "unqualified" I mean simply being without the very basic resume bullet points that anyone running for president prior to the current era would consider absolute bare necessities to even gain a major party nomination.

Let's start with Bill Clinton, a longtime governor of Arkansas, a small state that consistently ranked in the bottom five of every key economic and educational metric in the nation. He had no foreign policy experience. And most glaring of all, he had gone out of his way to avoid the draft during the Vietnam War.

If you had asked 100 random voters in 1980, 1970, or 1960 if such a man could even come close to winning the White House, most of them probably would have laughed. But Bill Clinton won in 1992, and beat an actual war hero in President George H.W. Bush. The kicker was that the elder Bush had some of the most extensive experience in foreign policy and government service of any candidate in American history.

Eight years later, it was George W. Bush who defied those qualification odds to beat a two-term vice president in Al Gore, who had been a longtime congressman before that, and even had some in-country experience in Vietnam. By contrast, the younger Bush had evaded serious duty during Vietnam with a coveted slot in the Texas Air National Guard, owned an almost empty list of accomplishments in the private sector, and had served without great distinction as Governor of Texas for six years prior to the 2000 election.

Eight years after that, a state senator named Barack Obama arrived on the scene. He had almost no record to speak of as a state senator from Illinois, and not much more on his resume from less than one term as a U.S. Senator. Yet he defeated Hillary Clinton, on his way to overwhelming a major war hero in Senator John McCain, who also served in Congress for a generation.

And last year, a man who had never even run for office in Donald Trump defeated Hillary Clinton, who some people got in the habit of calling the "most qualified candidate for president in U.S. history."

With the exception of the Hillary Clinton loss, perhaps you could chalk up this trend to a decline in respect for military service. That is somewhat understandably brought on by the end of the Cold War, and the dwindling number of surviving World War II veterans.

The 'Dilbert' effect

More on the mark are cultural observers like "Dilbert" creator and author Scott Adams. Adams has long made a strong case that the more persuasive candidate wins the election every time. Qualifications don't really matter. Records and resumes don't really matter. Humans are emotional beings, and the candidate who connects with our emotions the best will win, period.

I think Adams is much closer to being correct here, but I'd add one small caveat. What the public perceives as the more persuasive personality can change, based on a number of exterior circumstances.

At the height of the Cold War for example, Bill Clinton could not have been a serious candidate for president... even for the Democrats. Note that the Democrats' most liberal nominee before Clinton was Senator George McGovern in 1972, who had still been a hero bomber pilot in World War II.

However, does this mean that these more persuasive candidates were the "wrong" choices? That's another partisan debate that will never really be solved across party lines. The point here is to try to explain something to those people who are still incredulous over Trump's behavior, or his lack of qualifications for the nation's highest office.

The fact is a very significant portion America is okay with it. And if you're someone who voted for any of the previous three presidents before Trump, you contributed to it. The folks who kept touting Hillary Clinton as the "most qualified candidate" were probably causing her a net loss in votes every time they said it.

We've had 25 years to get used to this. That said, perhaps the more jarring nature of the Trump presidency will wake more of America up to the fact that qualifications have become cheap in a political atmosphere where most voters distrust politicians inherently.

Make no mistake, the Trump phenomenon didn't just happen overnight. And as long as we give so much power to a candidate who can charm or otherwise stoke our emotions to get into the Oval Office, it's going to continue.

Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.