What makes a great leader? Management theorist Simon Sinek suggests that it’s someone who makes their employees feel secure — who draws staffers into a “circle of trust.”

Sinek opens his TED Talk with a story about Congressional Medal of Honor winner Captain William Swenson who, while in Afghanistan, ran into live fire to rescue wounded soldiers and pull out the dead. After helping one soldier into a medevac helicopter, the captain bent over and gave him a kiss before returning to rescue others.

It made a tremendous impact on Sinek who asked himself the question, “Where do people like this come from?” His first thought was, “They are just better people,” but he soon proved himself wrong.

The author of Start With Why: How Great Leaders Inspire Everyone to Take Action, Sinek discovered that it is the environment. “If you get the environment right, every single one of us has the capacity to do these wonderful things.” Sinek talked with many folks who we would call heroes and asked each one the question, “Why would you do that?” The answer: “Because they would have done it for me.”

Trust and cooperation are front and center for this kind of environment to exist. However, trust is a feeling and we can’t just tell people to trust us, to cooperate and to follow us.

Sinek goes on to explain that we have evolved into social animals from the days of the Paleolithic era to the early days of Homo sapiens when we lived and worked together in what he calls a “circle of safety.” It was inside the tribe, where we felt like we belonged. And when we felt safe amongst our own, the natural reaction was trust and cooperation.

The same is true today in a world that is filled with danger — where there are things that frustrate our lives or reduce our opportunity for success.

The only variables are the conditions inside the organization, and that’s where leadership matters, because it’s the leader who sets the tone. When leaders make the choice to put the safety and lives of the people inside the organization first, to sacrifice their own comforts and to sacrifice the tangible results so that people feel safe and know they belong, remarkable things happen.

Adds Sinek, “When we feel safe inside the organization, we will naturally combine our talents, our strengths and work tirelessly to face external dangers and seize opportunities for success.”

When leaders choose to sacrifice so that their people may be safe and protected, Sinek believes that the natural response is that, “They will give us their blood and sweat and tears to see that their leader’s vision comes to life. When we ask them, ‘Why would you do that? Why would you give your blood and sweat and tears for that person?’ they all say the same thing: ‘Because they would have done it for me.’ And isn’t that the organization we would all like to work in?”

I encourage you to check out Simon Sinek’s TED Talk.

I also encourage you to read a blog I wrote several years ago about “personal trust.” It is a topic that I think is vital to establishing and sustaining relationships of all kinds.