During a four-week period in March and April, the conservative watchdog Media Research Center found that CNN spent 730 minutes on the Republican race and 214 on the Democrats. Trump had 331 minutes of coverage and Clinton had 110, the MRC said.
CNN has drawn particular attention because its ratings have risen faster than its rivals and, unlike Fox News Channel and MSNBC, both parties are more likely to work with the network.
Some CNN employees have expressed concern, through internal channels, about Trump's airtime. Yet it fits the playbook of CNN chief executive Jeff Zucker, who believes in lavishing attention on big stories, be they missing planes or politics. Zucker, who declined an interview request, has vigorously defended CNN's coverage and said neither the network nor Trump should be punished for his accessibility.
Now that the primaries are ending, "the sort of free-for-all season is over," said Frank Sesno, a journalism professor at George Washington University and former CNN Washington bureau chief.
"All news organizations have an obligation to get serious and sober about how they are going to cover this, about the equity with which they cover it," Sesno said.
These discussions are already taking place informally and each day's coverage is planned with fairness in mind, said one television news producer, who spoke on condition of anonymity because of the issue's sensitivity. The producer predicted the party nominees would get equal time or close to it.
"You're going to see more coverage than you can handle of both of them," the producer said.
History shows how coverage changes with a campaign's focus. During the first four months of 2008, the novel candidacy of Democrat Barack Obama received 243 minutes of coverage on the broadcast evening newscasts compared with Republican John McCain's 138 minutes, Tyndall said.
Between Labor Day and Election Day, McCain had 212 minutes of coverage and Obama 185, Tyndall said. During the last three presidential elections featuring no incumbent (2008, 2000 and 1988), the eventual loser had more coverage time, although it was virtually even in 2000 — like the election itself. That's probably because the underdog takes more chances toward the end, said news consultant Andrew Tyndall.
Trump's accessibility and media consciousness — he recently called the CNN newsroom to point out an interview done on Fox News — is a complicating factor.
"The problem for the networks is you have one candidate who is far more wary of the media than she ought to be and you have another candidate who is far more eager to be in the media than the media ought to allow," Jamieson said.
Sesno said Clinton needs to "rip off the Bubble Wrap and engage" the media far more than she's probably comfortable with.
News organizations need to be careful with the extent to which they let Trump drive the agenda, he said.
"The rule book has been shredded," he said. "I'm concerned that the echo chamber of horse race, personality and charges and countercharges will eclipse the serious conversation about candidates and policies that we should be having."
This past week provided fresh evidence that there's a lot more to coverage decisions than counting minutes. Newsrooms were faced with a decision when Trump attempted to tie Clinton to 1990s-era controversies — the Whitewater real estate investigation and the suicide of a White House aide — where the Clintons were investigated and no wrongdoing found.
"The way Trump works is to lay a lot of things out there on the assumption that he's not going to be held accountable for them, but you'll tally them up to a distrust of Hillary Clinton," Jamieson said.
Journalists need to weigh a responsibility not to publish misleading information and play into Trump's strategy, with an obligation to report on the activities of the Republican candidate for president and report on examples of how he thinks, she said