During the height of the Iraq War, thousands of US Navy SEALs lead some of the toughest and most dangerous missions across insurgent-held cities in Iraq and Afghanistan. Jocko Willink is a former Navy SEAL commander who saw extensive combat action during the Battle of Ramadi, leading SEAL Team Three's Task Unit Bruiser (which included Chris Kyle, star of the film 'American Sniper'). He is also the author of "Extreme Ownership: How US Navy Seals Lead and Win."

A Silver Star and Bronze Star recipient for his service during the Iraq War, Jocko knows a thing or two about leadership in pressure situations. It goes without saying that lessons learned on the battlefield serve as poignant examples for leadership in action; after all, people's lives are at stake.

So without further ado, here are five powerful lessons that will change the way you view leadership forever.

1. The leader is ultimately responsible for the success or failure of the team

True leaders cannot blame one individual. If someone is underperforming, you need to give them the proper training, support and tactics to be successful. Doing this requires you to set your ego aside and look at things objectively.

A leader doesn't take responsibility for the team's successes, but bestows that upon subordinate team members. When he or she does this, junior members and leaders within the team develop a team mindset at every level of the organization. Efficiency increases and a high performing team is the result.

2. Good leaders don't make excuses, they find a way to win

As Jocko repeatedly says, there are no bad teams, only bad leaders. Using an example from Navy SEAL BUDS training, Jocko discusses how the right leader--effective, inspiring and clear with his objectives--can make all the difference. Leaders find a way to win by taking extreme ownership of a situation and raising the expectations of those around him. That is a hallmark of true leadership.

Leaders must set high standards and ensure the team delivers on those standards. It starts with the individual and then spreads to each of the team members until it becomes the culture--the new standard.

3. Leaders must understand the "why" and impart this general knowledge to frontline troops

At the height of the Iraq War, it was easy for morale to dip and agendas to become confused, especially during a time of shifting politics and pressure back home. Before every mission, Jocko would walk his team through an in-depth training session, and he made it abundantly clear why every decision, strategy and tactic was in place. When your life is on the line, you have to know why you're fighting; losing that edge could mean losing lives.

In the business world, your employees need to know why you're making decisions. A leader must also be a true believer in the mission in order to convince and encourage others. Leaders must understand they are part of something greater than themselves. And this must filter down to the lowest level members of the team. Remember, leadership isn't one person leading a team. It's a group of leaders up and down the food chain all working together towards one unified goal.

4. Ego clouds and disrupts everything

This lesson is particularly difficult for some business leaders to grasp, especially when your own abilities have already taken you far. On the battlefield, US Navy SEALs are taught to let go of ego because, quite simply, it's a killer.

Ego disrupts the planning process, the ability to take good advice, and the ability to accept constructive criticism. As soon as you think you're better or smarter than someone else, you shut off your capacity to learn and grow. As a true leader, you need to remain open to new ideas and ways of thinking.

5. When it comes to performance standards, it's not what you preach. It's what you tolerate.

During a competitive boat race in Navy SEALs BUDS training, six teams competed for victory. After the first five races, there was a clear split: Team A placed first after every single race, and Team F had finished dead last. Jocko and the other instructors wanted to try something: what would happen if they took the group leader from Team A and put him in Team F's boat?

Guess what? Team F won the next race. And the next. And the next. See, it wasn't because the crew weren't good enough. It's because the new leader in Team F's boat wouldn't tolerate anything but the best. He set a new performance standard through his action and lifted the achievements of those around him.