Mike Bush, the former Commissioner of the New Zealand Police, served for more than four decades in law enforcement – starting as an 18-year-old constable, serving as a detective, and promoting up through the ranks of this highly professional and respected organization.

The population of New Zealand is roughly five million people. About one in six New Zealanders are of Maori descent – an indigenous Polynesian community – and that community has historically been underserved. Building ties to the Maori community was a priority for Mike, as was recruiting more citizens of Maori descent to the department, so that the New Zealand Police better reflected the diversity of the country.

One of the initiatives Mike developed and promoted as Commissioner was something he called “Prevention First” – to change the focus of policing from a model of locking people up to a model of early intervention, designed to prevent crime in the first place. Mike knew that gave his officers more of an opportunity to help people and to keep them safe.

The New Zealand Police have long been leaders in community policing. More than half a century ago, the New Zealand Police dropped the word “force” from their name and to this day their officers do not routinely carry firearms. The New Zealand Police have a well-deserved reputation for integrity and decency, and Mike describes their efforts to earn and preserve that reputation and to serve the diverse communities in his country.

Though violent crime is relatively rare, Mike investigated some of the biggest and most interesting cases in New Zealand history, including the successful recovery of a five-year-old girl who had been kidnapped, and a cold case investigation of a young murdered woman, solved through ingenious forensic work.

And, while posted overseas for part of his career, Mike was a first responder to the 2004 Boxing Day tsunami that struck Thailand – where he was stationed – and many other south east Asian nations, killing almost one quarter of a million people. Mike describes how law enforcement officers from around the world responded to that horrific tragedy.

Mike Bush had a fascinating career in the New Zealand Police, ultimately running the service and leading its 13,500 men and women. He helped transform policing in his nation, and is widely regarded as a visionary law enforcement professional.

If you have thoughtful feedback on this episode or others, please email us at [email protected].

Find the transcript and all our previous episodes at MSNBC.com/TheOath