(CNN) It's not organized military opposition to President Donald Trump. But day by day, generals and admirals are publicly stepping up and directly giving the American public their views in ways that don't always match the Twitter rhetoric of their commander in chief.

Nowhere was that made clearer than in the recent video of Air Force Academy superintendent Lt. Gen. Jay Silveria speaking to cadets after racist slurs were posted on message boards of five black cadet candidates at the Air Force Academy Preparatory School: "If you can't treat someone with dignity and respect, then you need to get out. If you can't treat someone from another gender, whether that's a man or a woman, with dignity and respect, then you need to get out. If you demean someone in any way, then you need to get out. And if you can't treat someone from another race or a different color skin with dignity and respect, then you need to get out," the visibly furious general told his troops.

It's what happened next that gives pause. The video went viral. Social media filled up with messages from currently serving and retired officers applauding Silveria for showing unambiguous leadership especially in the wake of the racial violence in the Charlottesville.

One senior officer, who asked not to be identified posted on social media, "Leaders own problems. I'd follow this leader anywhere, anytime."

In Puerto Rico it's much the same, while Trump calls for local Puerto Ricans to do more, the three-star Army general in charge of military relief operations has another view.

Lt. Gen. Jeffrey Buchanan, within hours of arriving, said more help and more troops were needed: "It's not enough and we're bringing more in," he said. More helicopters are now there to ferry aid to remote areas -- something local truckers cannot yet do. A three-star commander is on the front line of one of the worst natural disasters to hit millions of Americans, speaking bluntly off-the-cuff, without White House spin-meisters in control of his answers.

There were two more significant comments that underscore the difference in how some military commanders and the President are approaching the fundamental issue of leadership. In the wake of Charlottesville, the four-star heads of each military branch -- Navy, Army, Air Force and Marine Corps -- tweeted about their own zero tolerance for racism in the ranks. Privately they all indicated it had nothing to do with Trump's post-Charlottesville comments, but as members of the Joint Chiefs of Staff, each of them knows the precise political environment in which they operate.

But then there was a very different tweet about Puerto Rico from Trump several days into the relief efforts. He tweeted: "The Fake News Networks are working overtime in Puerto Rico doing their best to take the spirit away from our soldiers and first R's. Shame!"

Look past the slap at the media. This is the President of the United States openly suggesting the spirit of the American soldier, sailor, airman or Marine could be broken. No military officials I have spoken to in recent days can readily recall an instance of another president saying anything like this.

Even Gen. Joseph Dunford, the Chairman of the Joint Chiefs, who has been reticent to speak publicly, acknowledged to Congress he differed with the President on the proposed total ban on transgender persons serving in the military: "I would just probably say that I believe any individual who meets the physical and mental standards and is worldwide deployable and is currently serving should be afforded the opportunity to continue to serve."

Why is all this so important? This is no open revolt of the generals. In fact, many in the military support Trump because he gives top commanders more leeway to conduct operations.

And is this not exactly what we expect our senior military officials to do? Speak truth to power, which is not just the President but actually the American people? Until recent weeks, you haven't heard much publicly from military leaders. But that may be changing if these generals are a barometer.

Retired Col. Steve Warren, who served as a spokesman for Defense Secretary James Mattis, finally publicly decoded what has been happening in an interview on CNN's "Reliable Sources." It's much more than reporters saying they don't have access to information: "The secretary of defense is in a very tight spot," Warren said. "The President has declared that the press is the enemy of the people, but on the other hand I think Secretary Mattis understands the Pentagon is responsible for more than half a trillion dollars every year. There's a million American sons and daughters in harm's way."

All of this boils down to one point: Mattis and his generals don't want to upset Trump. But reality is setting in and that environment might not last much longer.

Even Republican Chairman of the Senate Armed Services Committee Sen. John McCain, who is close to Mattis and Dunford, criticized the Pentagon's failure to inform Congress especially about the war in Afghanistan.

"We expect -- indeed, we require -- a regular flow of detailed information about this war," he said.

Nowhere is the potential harm of not speaking truth to power more dire than North Korea. The President recently tweeted he told Secretary of State Rex Tillerson "that he is wasting his time trying to negotiate with Little Rocket Man... Save your energy Rex, we'll do what has to be done!"

The Pentagon has also strongly supported diplomatic action even as it plans for military action if needed. Top generals have consistently supported diplomatic efforts leading the way.

Mattis has insisted for months he has no differences with Trump: "If I say six and the President says half a dozen, they're going to say I disagreed with him," he recently told reporters.

But even for Mattis, that may be a message point that is hard to stick to. He told Congress Tuesday he believes it's in the US national security interest to remain in the nuclear agreement with Iran. He also strongly endorsed Tillerson's efforts t o keep working on diplomatic solutions to the North Korea crisis.

There's no indication Mattis is on the outs with the President. And Congress understands, even if some don't agree, his political sensitivities when dealing with the Trump White House. But there is one problem: It is beginning to look like some generals plan to keep saying exactly what they think as they exercise the military leadership they believe is fundamental, and if that means contradicting the commander in chief, then so be it.

Lt. Gen. Vincent Stewart, one of the nation's most senior intelligence officers, made this sentiment clear in a speech Tuesday: "Never forget who we serve. The Citizens of the United States."