Much is being made of everything Donald Trump says these days. He takes a swing at an opponent, and it's a headline. He cracks wise about whining, and the Internet goes crazy. He grabs a bagel for breakfast, and the crowd roars. In short, he's the political equivalent of Miley Cyrus swinging in on her wrecking ball and he’s got the kids going wild.
 
Still, the most important thing he has said lately was nine words at the start of that GOP debate. Asked if he would rule out running as an independent, Trump said “I will not make that pledge at this time.”
 
This is a big deal.
 
First, it reveals that Trump knows what many experienced political hands are whispering – he’s entertaining, he’s rocking a powerful anti-government meme, but it won’t last; becoming the Republican Party’s nominee is still a very long shot.
 
Second, it shows that Trump understands the power of an independent threat. In the past five presidential elections, the margin of victory has averaged 4.5 percent of the popular vote. So if an independent took just that much away from one party, he or she could dramatically affect the results of the election. That means if Trump runs as an independent, he could hand the election to the Democrats — or coerce concessions from the Republicans in exchange for not doing so.
 
It’s possible. In 1992, Ross Perot – another ambitious billionaire businessman –ran as an independent and took 19 percent of the popular vote. Politicos have argued ever since about how much that contributed to Bill Clinton’s victory over George H.W. Bush, but Perot undeniably changed the math.
  
Make no mistake: running as an independent could cost Trump a half-billion dollars, and the confluence of opposition money, election laws, and party machinery would make victory almost impossible. But even if he loses, he could still have a say in who wins.
 
And that’s not a bad return on investment. 
 
Tom Foreman is a CNN correspondent and author of the upcoming book "My Year of Running Dangerously"