The Twitter stream on a producer's computer a few feet from where Fox News Channel's Shepard Smith anchored his newscast several days ago steadily churned out invective. You're a liberal, Shep. You belong on MSNBC. President Trump doesn't watch your show.

Those are the printable messages, and illustrate the island he often finds himself upon.

Fox is the network of choice for an overwhelming majority of Trump supporters and Smith's afternoon newscast is the place where they are most likely to encounter things they might not want to hear. In the past week, he pointed out that facts don't support the president's claim of widespread voter fraud. He said he doesn't know upon what Trump bases his belief that torture works as an interrogation tactic, and said the new immigration policy is a jihadist's dream. "We know because they've said so for years," he said.

And Trump's claim that the media is the administration's opposition party? Smith calls it preposterous.

"We're the Fourth Estate," he said in an interview. "We work for the people. It's our job to find out what's happening, to provide context and perspective and give them information that's fair and truthful and as perfect as we can make it. The suggestion that we're the opposition party is not worthy of a reply."

It's his job to point it out if it's clear the president is not telling the truth, he said.

"This is new territory for us," he said. "People who are partisan will say, '(Obama) said you can keep your doctor and you couldn't,' This isn't the same thing. This is a demonstrable, of-the-moment utterance. When it's demonstrably false at the moment of utterance, it's not really difficult to figure out what to do next. This dynamic of the president not telling the truth in a public forum, it's new to me."

Smith's show airs seven hours before Sean Hannity, who has continued his Trump advocacy while sharpening his attacks on media outlets that question the president. In an interview with Politico released this week, Hannity said The New York Times, CNN and MSNBC "will never get their credibility back" if they have people on the air who call Trump a liar.

While he may not use the l-word, Smith said it has never been more important to have people whose job it is to find out what's happening and get it right.

"People who are not appreciating that right now — and I understand that nerves are raw — there will come a time when they appreciate that," he said.

The 53-year-old anchor is a lifer at Fox News, which this month marks 15 years as the most-watched cable news network. His boss, Fox News executive vice president for news and editorial Jay Wallace, praises Smith's ability to take command of a big story and explain it to viewers without talking down to them.

Fox executives have always taken pains to contrast its news programs from opinion, and Smith's work has always been one of the most frequently cited examples of the former. Wallace said that when the time comes to challenge people, Fox will. Megyn Kelly's famous troubles with Trump and Chris Wallace's sharp questioning during a presidential debate prove his point.

Yet to many viewers, opinion is inherent in news choices: how much time a network gives to covering demonstrations against Trump's immigration policies, for example, or which political point of view is better represented among commentators on panels. On Inauguration Day, Fox made the decision to "let it breathe" in contrast to competitors who were giving poor marks to the new president's inaugural address, he said.

"We may not have been antagonizing him from Day One like the other networks," Jay Wallace said.

When former Fox News chief executive Roger Ailes left under the cloud of sexual abuse allegations last summer, Smith worried about the future, like everyone around him. He was assured when Rupert Murdoch told him he wanted to make a bigger commitment to breaking news. "Music to my ears," Smith said.

The bulk of that news commitment will come in digital, however. Starting with Smith's move from the early evening to afternoon in 2013, Fox News Channel's trend has been to sharpen its opinion programming. Conservative Tucker Carlson took over in prime time upon Kelly's exit (although the newsier Martha MacCallum took over Carlson's 7 p.m. time slot) and Bill O'Reilly's ambush interviewer Jesse Watters earned his own weekend show.

The results are hard to argue with. Carlson's ratings have eclipsed Kelly's in only a month and Fox has avoided the sharp downturn in viewership that news networks typically face after an election. Smith's ratings fall in the mid-range among daytime Fox hosts, and, like most Fox News shows, have higher viewership than shows on MSNBC and CNN in the same time slot.

"We know that that sort of thing seems to score," Smith said. "People like to watch opinion television."

If that's what Fox wants for its prime-time lineup, "that's fine with me," he said, "especially since we have the promise that when big news breaks, we'll be in there."