If you believe the political historians, debates almost never change the trajectory of a presidential campaign. Well, we've witnessed a lot of things in recent months that "almost never happen" or could "never happen," and I suspect that we're about to see another one. This debate has the potential to matter a great deal.

The stage has certainly been set. Donald Trump has closed the polling gap with Hillary Clinton, the two campaigns have been attacking each other with bitter ferocity and around the country, as people have taken sides, friendships and families are being rent to a degree unprecedented in living memory. This election season is no longer a contest between candidates or political campaigns. It has become a collision between two profoundly different world views, and it's not an exaggeration to say that its outcome could alter the course of American history. Even many Americans who don't typically follow politics have become very, very aware of what's at stake.

A few weeks ago, in fact, Trump complained because the debates had been scheduled against NFL football games, and he worried that nobody would watch. I don't think that's going to be a problem, not even here in Atlanta with the Falcons on Monday Night Football against the hated Saints.  Why watch stylized violence and a contrived contest pitting "us" against "them" when a high-stakes version of the real thing is just one click away on your remote?

The night's message from the Trump campaign will apparently be that it's time for a change, and that only he is capable of forcing the scale of change necessary in Washington. I suspect that's true, at least to the degree that a President Trump would indeed force large-scale change in ways that even now are difficult to imagine. But it's important to remember that change is a neutral term. Things can change for the better; they can also change for the worse. And eight years ago this month, they were changing dramatically for the worse.

In late September of 2008, Lehman Brothers had just declared bankruptcy, and the Federal Reserve had announced a takeover of AIG. The stock market was in free fall, President Bush was warning that "this sucker could go down," and U.S. Sen. John McCain had suspended his campaign to return to Washington in a panic, demanding that his debate with Barack Obama be postponed. (Obama declined, pointing out that “part of the president’s job is to deal with more than one thing at once.")

The situation was so dire that at one point, Treasury Secretary Henry Paulson got down on one knee in front of House Minority Leader Nancy Pelosi, begging for her help with passage of a financial rescue package.

“It’s not me blowing this up, it’s the Republicans,” Pelosi said.

“I know," Paulson responded. "I know.”

On Sept. 29, 2008, despite warnings from Bush, Paulson, John Boehner and other top Republicans that killing the financial rescue package would produce an economic train wreck rivaling or exceeding the Great Depression, GOP members voted overwhelmingly to take that risk. In fact, many of them seemed almost gleeful about their vote. They wanted change, and if that change could come about only by allowing the entire economic system to crash down around them, putting millions more out of work and destroying the retirement plans of millions more, they were perfectly willing to do so. It was an earlier expression of the same destructive sentiment now animating much of the Trump campaign

Sure enough, on the day of the bill's defeat, the Dow suffered its worst one-day decline in history. But in Congress, unlike in presidential elections, you can always get another chance to vote. Five days later, the rescue bill did finally pass the House, averting almost certain disaster, even though a majority of House Republicans still voted against it. To this day, voting in favor of the bill that saved the global economy, with every dime eventually repaid to taxpayers, is considered the mark of Cain among Republicans.

Since the depths of the Great Recession, the Dow has almost tripled in value and we've added almost 15 million jobs to the economy. The jobless rate is 4.9 percent, and last year median household income increased by 5.2 percent, the single largest increase in the 50-year history of that statistic. While that too is change, it is change for the better. I'm still not quite sure why millions of our fellow Americans refuse to recognize that progress, or are so willing to once again march us toward the abyss. I do know that I'll be watching tonight to see if Donald can explain it to me.