Watching a presidential debate is a bit like watching a NASCAR race: Folks want to see who wins the flag, but they also want to see who hits the wall. And boy, are they tuning in.
The first Republican debate drew 24 million viewers, the largest audience ever for a non-sports show on cable TV. The second GOP contest was almost as popular. The Democrats pulled in 15.3 million viewers, far ahead of the party's record in previous years.
So why the huge interest? There is little hard evidence, but plenty of informed speculation. Here are four possible reasons.
-- Trump. Love him or hate him, the explanation has to start with Donald Trump. Like Ronald Reagan, he understands television extremely well. The medium, by its very nature, focuses on vivid personalities -- especially personalities who prize conflict and confrontation.
Jeb Bush made this point recently when he described Trump on CNN: "It looks as though he's an actor playing a role of the candidate for president ... Mr. Trump talks about things as though he's still on 'The Apprentice.'"
All true, and Bush is right in adding that Trump is a cynical showman who does not take the "the possibility of being president of the United States really seriously."
But it's also true that performance skills are a critical part of the job, and Trump has them. As Reagan once shrewdly observed, "How can a president not be an actor?"
Trump's not the only star on the campaign circuit. The field is full of firsts worth watching. Ben Carson would be the first black neurosurgeon in the White House. Bernie Sanders would be the first Jewish Social Democrat. Hillary Clinton or Carly Fiorina would be the first woman. (Jeb, by contrast, wouldn't even be the first son of George and Barbara Bush.)
-- Unpredictability. Public interest has been stoked by the twists and turns of a plot tailored for reality TV. There is no incumbent. Both races remain open. No one -- including us -- has any idea who will be left on the island after the final episode. Joe Biden couldn't decide for months whether to join the cast at all, before finally saying no.
Trump and Carson were supposed to fade. Rand Paul was supposed to have a fresh message. All those governors -- Walker and Perry, Christie and Kasich -- were supposed to harness anti-Washington animus. Clinton and Bush were supposed to raise enough money to overwhelm their opponents.
None of that has happened.
-- Social media. The Pew Research Center reports that two-thirds of American adults now use social media, which is a tenfold increase in 10 years. The rate rises to 90 percent for young adults. And 2 out of 3 social media mavens use those platforms to learn about, or participate in, politics.
The full impact of this surge remains unclear, but it certainly seems connected to the rise of candidates who are independent brand names, fluent at communicating directly with their followers, outside traditional party and media channels.
Trump is not only a reality TV star, he's also a "natural born" Twitterite, writes Nicholas Carr on Politico, deftly using that platform to inject his views into the center of the political conversation.
"What Trump understands is that the best way to dominate the online discussion is not to inform but to provoke," Carr explains, and Sanders understands the same point. "It's the crusty Bernie and the caustic Donald that get hearted and hashtagged, friended and followed."
-- Polarization. "Republicans and Democrats are more divided along ideological lines -- and partisan antipathy is deeper and more extensive -- than at any point in the last two decades," reports Pew.
In decades past, conservative Southern Democrats and progressive Northern Republicans balanced and buffered the extreme tendencies in both parties. Whoever won, from either party, would have to govern from the middle.
That's no longer true. America is approaching a European model, divided along ideological lines, with a liberal party called Democrats and a conservative party called Republicans.
One likely result: Voters feel this election is more critical than usual. So they are more interested and engaged, especially if they are more purist in their politics.
"Many of those in the center remain on the edges of the political playing field, relatively distant and disengaged," writes Pew, "while the most ideologically oriented and politically rancorous Americans make their voices heard through greater participation in every stage of the political process."
So the stakes grow higher as the outcome grows dimmer. That's why so many viewers tune in to see who rises up -- and who flames out.