President Trump dealt a severe blow to the Clinton dynasty when he unexpectedly defeated Hillary in the 2016 election. But as his first year in office comes to a close, Trump threatens to discredit yet another of the Clintons' key political insights: It's the economy, stupid.

It's an adaptation of a phrase coined by longtime Clinton consigliere James Carville that alongside "Change vs. more of the same" and "Don't forget health care" was among the pillars of Bill Clinton's successful campaign against President George H.W. Bush in 1992. Trump was arguably only one for three when he won in 2016.

But Trump is undermining the idea that the electorate is "focused like a laser beam on the economy" to his own detriment. If that was as true now as in the past, the current occupant of the White House would be a lot more popular.

We are on track to end the year with a 4.1 percent unemployment rate, a 17-year low. The economy grew by 3.2 percent last quarter, only the second example of consecutive quarterly growth in excess of 3 percent in three years. The U.S. added some 1.7 million new jobs in year one of Trump.

You can poke holes in these statistics, as Trump did himself when he painted a dismal picture of the economy during the campaign despite generally favorable data. Labor force participation rates are still low by historical standards, suggesting some of the jobless have stopped seeking work entirely. Others are employed in jobs that pay less than the ones they lost in the recession. Growth isn't shared equally, with a few parts of Trump Country lagging. Health-care costs continue to eat into family incomes.

One can even quibble over how much better economic conditions are under Trump than former President Barack Obama, who certainly inherited a worse economy from his own predecessor. Of course, the recession Bill Clinton ran against in 1992 under the "economy, stupid" theory had actually ended before he even formally declared his candidacy, so these things are par for the course.

Still, the economy is doing well enough for Trump to reap some political benefits. Instead his job approval rating sits below 40 percent in the RealClearPolitics polling average, with 56.2 percent disapproving. A recent Reuters/Ipsos survey found only 35 percent approval, 60 percent disapproval. Democratic congressional candidates are favored by nearly 13 points in the generic ballot while 59.3 percent of Americans think the country is on the wrong track.

If it was all about the economy, Trump's approval rating should be better than 50 percent. Yet 60 percent view the president unfavorably in a recent CNN poll. Economist/YouGov pegs that figure at closer to 54 percent.

Conservatives accused the Clintons of coarsening the culture throughout the 1990s, especially during the Monica Lewinsky scandal that led to the 42nd president's impeachment 19 years ago. Voters largely ignored these complaints, which were drowned out by an internet-fueled economic boom.

But under Trump, the electorate seems more worried about presidential coarseness even as the economy is on the cusp of realizing its potential for the first time in years. Trump's toxicity with college-educated suburban voters, especially women, threatens Republican congressional majorities next year, even as those majorities help him deliver tax cuts and deregulation that could make the economy grow faster still.

In between his fiercely loyal base and the equally rabid "Resistance," Trump fatigue appears to be setting in. "I thought that Trump was actually driving people to want to end the chaos," Democratic strategist Joe Trippi told Vox's Ezra Klein, explaining Doug Jones' upset victory in Alabama over Roy Moore. "Even if you liked him, you didn't want more chaos in Washington than what he was already creating."

"My gut is that for Democrats, the winning message in 2020 is basically, 'It doesn't have to feel like this,'" Klein concurred. "I think most people do not want politics to feel like this. They don't want it to take up this much space in their heads. They don't want it to feel as conflictual with their neighbors. The whole thing feels terrible."

This observation is backed up by anecdotal evidence, at least. Swing voters who say they no longer watch the news; friends who say they stay off Facebook to avoid their neighbors' Trump diatribes, pro or con; complaints about the president's own social media habits.

Maybe voters will get used to it. Perhaps over time the economic data will be more determinative than the anecdotes, especially if the Republican-celebrated tax bill delivers on cuts and growth against the public's expectations.

If not, Trump may erase another piece of the Clinton legacy — at the expense of his own re-election chances.