MIAMI — For all of the cable news chatter, Twitter skirmishes and presidentially bestowed nicknames, this week’s prime-time Democratic debates mark the entry point for millions of Americans who are just now tuning into a contest that will dominate news coverage for the next 16 months.

It’s also the starting gun for a media frenzy that is poised to outstrip even the coverage of the raucous 2016 campaign. NBC is pre-empting four hours of lucrative weeknight programming for a two-night showcase that could draw 20 million viewers, by far the biggest platform of the primary season so far. Roughly 700 journalists will descend on Miami on Wednesday, a reminder that in the era of Donald Trump, television still has the power to determine candidates’ destinies.

“Network news still assembles the largest marketplace, the largest public square of any form of news,” said Martin Kaplan, director of the Norman Lear Center for media and society at the University of Southern California.

Crew members Tuesday were completing the high-tech debate stage at the Adrienne Arsht Center, which is dominated by 600 square feet of screens displaying a wraparound image of the White House. Slim Plexiglas lecterns, emblazoned with the presidential seal, stood in a tight semicircle, a concession to the crammed slate of candidates.

“It’s a much thinner design than we’ve done in the past,” Marc Greenstein, the NBC executive in charge of design, said as he gestured toward the lecterns. “We wanted to keep the intimacy, even though we have 10 people.”

More than 200 news outlets — including ones from Australia, China and Japan — are on hand to cover the two debates, though reporters and the candidates will be physically separated: The media headquarters and so-called spin room, where campaign operatives roam, are across the street from the debate hall.

For NBC, keeping things coherent is paramount. Ten politicians mean that cross talk and spotlight-hogging are inevitable. Five network personalities are sharing moderating duties.

“Our focus is trying to maintain decorum as much as we can,” said Rashida Jones, the NBC executive overseeing the event. “A lot of this we’ll have to determine in real time. We don’t want the experience for the viewer to be so chaotic that they can’t hear and absorb what people are saying.”

Then there’s the Trump wild card: The president has already mused about live-tweeting the proceedings. Jones said that NBC did not have a specific contingency plan for that. “Anything that happens before and during the debate, we put through the same news lines of, ‘Is this worth incorporating into the conversation?’ ” she said.

A presidential race carries great public import — but commercial priorities are at play, too. Politics is big business for TV news, an aging medium that has enjoyed bigger viewership and profits since Trump came on the scene. A Pew Research Center study Wednesday found that the average combined prime-time audience of CNN, Fox News and MSNBC increased 8% in 2018 from the previous year. Revenue across the three networks was up 4% in 2018 to about $5.3 billion, the study said.

The heightened interest has changed the calculation for the major broadcast networks that, four years ago, declined to air presidential primary debates on weeknights, because they were reluctant to preempt lucrative entertainment programming. Weeknight debates were mostly relegated to cable news, which draws a smaller audience than national broadcast affiliates.

And unlike in past years, when primary debates were mainly the dominion of political junkies, these first debates have spawned a TV cottage industry that can reach a broader variety of viewers, with late-night hosts like Stephen Colbert, Trevor Noah and Seth Meyers offering live analysis after the event.

“Most of presidential campaigning is retail and incremental movement in the polls,” said Mark McKinnon, a veteran political consultant who himself became something of a TV star in the 2016 campaign, when he co-starred in “The Circus,” a Showtime reality series. “Debates are wholesale and an opportunity to really move the dial.”

Television’s importance to modern presidential politics was clear from the first Republican primary debate in August 2015. Trump’s slashing attacks on his rivals and subsequent feud with one of the moderators, Megyn Kelly of Fox News, made for riveting TV. The audience, 24 million people, remains a record for any cable news broadcast.

This week’s Democratic debates are simultaneously airing on MSNBC and the broadcast affiliates of NBC and Telemundo. Executives at NBC have sought to play down expectations for ratings, noting that four hours of debating across two nights is a big commitment for viewers. “It’s not about the numbers for this one,” Jones said. The first Democratic debate in October 2015 on CNN drew 15.3 million viewers.

Indeed, some campaign operatives say live viewership of televised political events can be less important than whether their candidate secures a viral moment. Feisty exchanges — or cringeworthy gaffes — can live for days on cable news talk shows and Twitter GIFs.

Barnstorming in Iowa and South Carolina still matters. But candidates who have embraced media exposure, like Mayor Pete Buttigieg of South Bend, Indiana, and Sen. Elizabeth Warren of Massachusetts, have seen firsthand television’s ability to boost name recognition and voter interest.

“What I think is ironically benefiting television is all the ancillary support and interest kindled by social media,” said Charles L. Ponce de Leon, a historian and author of “That’s the Way It Is,” a history of television news. “Rather than competing, social media and legacy television are working synergistically. That in turn compels candidates to appear on legacy television to enhance or correct the previous news cycle.”

The election coverage will also be a major test for individual network journalists, whose role as campaign referees has become more complicated amid Trump’s attacks on the news media and the increased polarization of the news.

A move by Democratic leaders to exclude Fox News from hosting debates turned into a major issue in the party primary. NBC raised some eyebrows by including Rachel Maddow, the MSNBC opinion host, among its moderators this week, though the network noted that she previously moderated an MSNBC debate in February 2016. (The other moderators are Savannah Guthrie, Lester Holt, Chuck Todd and José Díaz-Balart, of Telemundo.)

Kaplan, of the Norman Lear Center, offered a broader concern: that the collaboration between political parties and financially motivated television executives may not necessarily leave the public better off.

“Why is it that a network gets to monetize our election?” he said. “It’s a financial transaction between democracy and the media industry. Politics has effectively merged with entertainment, because both these entities are in the attention-capture business.”

But will Kaplan be tuning in Wednesday?

He laughed. “Of course.”

This article originally appeared in The New York Times.