What is the difference between state law enforcement and metropolitan police?

Answer 1

Depends on the state you are in. Most states a law enforcement officer is licensed by the state and just works for a certain department but no difference in the license. So basically the only difference is in the department they work. The job they do is similar in nature.

Additional: A municipal or city officer has jurisdiction/authority to exercise their powers only within their municipality. A county officer or sheriffs deputy has authority to operate within their county AND any municipality or city within it. A state officer (trooper/patrol/police) has authority to operate anywhere within their state.

Answer 2

I could write a book on this subject, but I'll try to keep it as short (and clear) as I can for you.

The primary difference is the jurisdiction that the two hold. Local law enforcement agencies (or, metropolitan police, as you called them) hold jurisdiction over their particular city.

For example, the Phoenix Police Department may enforce the laws of Phoenix, the laws of Arizona, and laws of the United States. However, they may only enforce those laws with-in the city of Phoenix. As soon as a Phoenix Police Officer enters Scottsdale (a neighboring town), the Phoenix Officer no longer has authority.

Now, the Arizona Criminal Investigative Division (CID), which is a state law enforcement agency, has authority over the entire state of Arizona. An agent of the Arizona CID has authority over, both, Phoenix and Scottsdale, and any other city with-in Arizona. However, a CID Agent CANNOT enforce city laws. If the infraction of "speeding" is set by Phoenix Law, then a CID Agent does not have the authority to enforce that law.

Policies regarding the federal government are similar.

Don't view it as "one outranks the other", but instead view it as "each has a different job".