Dad, what's the difference between a Police Officer and a Soldier?

From a Libertarian perspective: the purpose of the police is to defend your life, liberty, and property from internal aggressors. The purpose of the military is to defend your life, liberty, and property from foreign aggressors.

I guess in 9 y/o language it would be that police are suppose to protect you from bad people near home, and the military is supposed to protect you from bad people from far away? lol I'm not very good at communicating with children.

This is a complex question.

Soldiers Defend an Ideal (the Spirit), Police Defend the Law (the Letter).

They are two sides of the same coin.

I don't want to delve too deeply into this, without making it overly complex (at the 9 year old level), but this should be a good starting point.

My daughter, when she was about 5 asked me where I was going when I as about to deploy. I told her I was going to work in a different country to to fight bad guys so I and other Army Soldiers could protect her and mommy and everyone else in America. She looked at me, made a fist and made a punching motion and said, "Are you going to POW the bad guys in the face?" Man that made me smile and I said, "Yes Sweetey, I'm going to POW the bad guys in face."

Lots of good answers here. I like this meme from one of my Sci-Fi shows which states the difference and why they should never be one.

Though I don't necessarily recommend sharing this with a 9 year old, at the base level, Police protect the community by enforcing laws and defending victims of crime, whereas the military enforces the political will of the US Government to defend its interests worldwide. The biggest difference is that a police officer has the right and possibly the duty to take a life in defense of their own or another person. The military generally needs a mission, but depending on their rules of engagement may defend their own lives or the lives of others. On some military missions, there have been some very interesting Rules of Engagement and a soldiers survival may not be the highest priority.

We always used to joke, that in law enforcement, you may have to make a decision in less than a second to take a life, that others may argue about for years. It was a grim reminder of what many police officers have to face. None of them want to make a mistake and take a life, but the higher the stress level, the more likely an incident will occur. That's why you should insist on well trained and paid police professionals on your police force with community involvement.

Both police and soldiers preserve, protect, and defend the Constitution within the scope of their respective missions.

Police investigate crimes and apprehend criminals. Soldiers destroy the ability of enemies to make war on our nation and our citizens.

We the People protect ourselves and our nation by supporting both police and soldiers and through intelligent participation in our limited representative government which establishes and maintains both the military and police organizations.

Pretty soon, this will be it:

http://www.youtube.com/watch?v=9bOQitInC84

"We're police officers. We're not trained to handle that kind of violence."

Soldiers defend the nation and the Constitution is the nation. The United States of America could exist anywhere that We the People proclaim our sovereignty in its terms. It defends it from all enemies, foreign and domestic.

Law enforcement officers investigate crimes and apprehend perpetrators. Prosecutors, also law enforcement officers, complete the work of investigation and present cases against perpetrators. In this manner they also defend the nation/the Constitution, albeit in a more subtle way.

One of the principle differences between them is that soldiers confront enemies as they attack the nation/the Constitution. Law enforcement officers may confront perpetrators on those rare occasions when they come upon a crime during its commission. All too often they arrive just in time to draw a chalk outline around a body or dust for fingerprints. If soldiers arrived that late, the nation and its Constitution would be lost.

Thanks for the responses everybody. I will be sitting down with her later and explaining this a bit better for her. Again, thanks much.

My advice is to first read, and understand this quote from James Madison from the Federalist Papers...
“The powers delegated by the proposed Constitution to the federal government are few and defined. Those which are to remain in the State governments are numerous and indefinite. The former will be exercised principally on external objects, as war, peace, negotiation and foreign commerce. ... The powers reserved to the several States will extend to all the objects which in the ordinary course of affairs, concern the lives and liberties, and properties of the people, and the internal order, improvement and prosperity of the State.”

Then it should be easy to explain that the Army's job is to protect ALL of the States of the US from bad people in other parts of the world, or to defend the US from invaders, or those who would attack our great country.

The job of the police is much closer to home. Their job is to protect our States, Cities, streets, and homes from criminals who would want to do harm to our local businesses, homes, property, or persons.

I hope this helps to delineate the differences. Clearly you'll have to translate these thoughts into age appropriate language for your daughter.