Omarosa Manigault Newman, the former top Trump aide and purveyor of a scathing memoir, has given the president a cautionary tale. She and President Trump go way back to their days on “The Apprentice,” and yet she still stabbed him in the back after being fired. Mr. Trump had thought he could trust the people who were with him before he won the presidency, according to his first campaign manager, Corey Lewandowski, the guest at Wednesday’s Monitor Breakfast. But no more. “Life is tough,” Mr. Lewandowski said. For Trump, loyalty is key. And despite the fact that Lewandowski, too, was fired by Trump, he remains loyal. He signed a non-disclosure agreement, but he thinks such agreements are unenforceable. The two talk often, and Lewandowski appears on stage at Trump rallies. Presidential scholar Matt Dickinson explains the value of keeping up with friendly “formers": They’re a source of support, and can give objective advice, he says. “They also can rally support for you without the encumbrances of holding an official position.”

What's the difference between Omarosa Manigault Newman and Corey Lewandowski? Loyalty to the boss – Donald Trump – who hired and fired you.

In the case of Ms. Newman, once President Trump’s top African-American aide, her firing last December gave way to a firestorm with the publication of her tell-all book, “Unhinged: An Insider’s Account of the Trump White House.” Her most explosive, and so far unproven, charge is that a tape exists of Trump using the N-word to refer to black people.

With Corey Lewandowski, the president’s first campaign manager, “you’re fired” was barely a speed bump along the path of a still-warm relationship.

Mr. Lewandowski’s own book, “Let Trump Be Trump” – co-written with former deputy campaign manager David Bossie – is full of over-the-top paeans to the boss who fired him in June 2016.

Speaking Wednesday at a Monitor Breakfast for reporters, Lewandowski acknowledges that he signed a nondisclosure agreement in January 2015 when he agreed to run Trump’s presidential campaign. Still, he makes clear he thinks such agreements are probably unenforceable.

Not that it matters. One gets the strong sense that Lewandowski would be just as laudatory toward Trump, with or without a nondisclosure agreement. He launched his breakfast remarks by citing positive polling data from CNN.

“This president … is as popular as Ronald Reagan, Jimmy Carter, or Bill Clinton at the same time of their first term in the presidency,” Lewandowski said.

These erstwhile aides represent the two universes of Trump “formers”: those who remain loyal and provide an emotional lifeline to a president who reportedly feels besieged at times; and those who, like Newman, have embarrassed him and raised questions about his hiring decisions.

Add to the latter category Paul Manafort, who served as Trump's campaign chairman. He's on trial for tax evasion and bank fraud; his sidekick, Rick Gates, has testified against him in a plea deal. Technically, Mr. Manafort has remained “loyal” to Trump, in that he has not taken a plea deal (but it’s not known if one was even offered).

Still in the orbit

Among the top-level “formers” still very much in the Trump orbit is Hope Hicks, the former communications director who resigned in February. She recently visited Trump and family at his Bedminster, N.J. club, then joined the Trump team on Air Force One for a “Make America Great Again” rally in Ohio. Add to the loyal “formers” Sean Spicer, who served as press secretary for Trump’s first six months in office. His book, “The Briefing,” safely avoided criticizing the (former) boss. And he’s also signed on to serve as a spokesman for a pro-Trump super-PAC called America First Action.

Lewandowski is a senior strategist for Vice President Pence’s political action committee, the Great America PAC. And unlike Spicer, who came to Trump from the world of establishment Republican politics, Lewandowski is more an outsider, like the boss.

Lewandowski and Mr. Bossie are also regulars on Air Force One, flying with Trump to “MAGA” rallies. The president often calls them up on stage, where Lewandowski shows his skill at energetically channeling Trumpian messages.

Presidential scholar Matt Dickinson of Middlebury College says there is value to a president of keeping up with friendly “former" aides. “They’re a source of support, and can give objective advice,” he says. “They also can rally support for you without the encumbrances of holding an official position.”

Trump is known for having a stable of outsiders he likes to talk to, from Fox News commentator Sean Hannity and Newsmax publisher Chris Ruddy to Lewandowski and former New York Mayor Rudy Giuliani, who is a legal counsel to Trump on special counsel Robert Mueller’s investigation into possible collusion between the Trump campaign and Russia.

All presidents, of course, have a “kitchen cabinet,” the friends and aides who knew them before they reached the Oval office and could be trusted to have their best interests at heart. That’s why Omarosa’s turn against Trump has reportedly been so shocking to him, as reflected in comments and tweets where he calls her a “dog” and a “low-life.”

The betrayal of Omarosa put the lie to Lewandowski’s assertion in April that anyone who was with Trump before Election Day in 2016 is a “loyal, dedicated person,” whereas anyone who joined the team later was suspect. At the Monitor Breakfast, Lewandowski was asked why Trump has been beset by record-high turnover.

“Part of what people still tend to forget about this administration is, Donald Trump came to Washington with no political experience, never having run for office before, and never having had a group of individuals who had served him as an elected official,” Lewandowski said.

The outsider who wasn't ready to go

Trump’s lack of political and governing experience, of course, was one of his selling points as a candidate. Americans wanted something different, and they got it, Lewandowski stresses. But he also lightly raps the Trump team’s knuckles for the messy start to his presidency.

“One of the biggest mistakes this administration has made was that they weren't ready to go on Day One,” he says.

Lewandowski was also asked, as the father of four young children, how he feels about the harsh language Trump has aimed at Omarosa.

“You know, I have to tell you, I grew up in Lowell, Mass., not exactly Cambridge,” he says. “A little different, a little tougher than Cambridge, Mass.… Life is tough.”

Lewandowski says he has tried to explain to his kids, who range in age from 7 to 11, that he wants to help put the country on a different path, and that means tough decisions and tough language.

“Is it great to go and insult people and chastise them in public? Maybe not,” he says.

“But I also think by and large the American people want results. And they had the opportunity to go and vote for political correctness time and time and time again in the primaries, and they chose to vote against the standard operating procedure of how Washington’s worked, and do something different. And I think Donald Trump is delivering on that promise.”