In the NPS, US Park Rangers hold two different types of commissions. See Below. Once you graduate from the Seasonal academy you hold a TYPE II Commission. After graduating from FLETC you hold a TYPE I commission. THe main difference between the two if you have graduate from FLETC yet or you are a graduate of the Seasonal Academy (eventually going FLETC).
Thimios315 can elaborate more. PM me if you need more info. I work for the NPS with Thimios315.
Congress has authorized the Secretary of the Interior to designate certain employees of the Department of the Interior as law enforcement officers, with the responsibility to "...maintain law and order and protect persons and property within areas of the National Park System" (16 U.S.C. 1a-6(b)).
Only employees commissioned under this authority will perform law enforcement duties. Law Enforcement Commissions are issued only to employees who have successfully passed the background investigation, medical exam (including psychological screening), physical efficiency battery, drug testing, and rigorous training requirements. Each chief park ranger is responsible for certifying to the park superintendent that commissioned employees meet training and qualifications standards set forth in RM-9.
The two types of commissions are the Type I (full authority) law enforcement commission and the Type II (limited authority) law enforcement commission.
5.1.1 Type I Commissions
These commissions are held only by permanent NPS law enforcement personnel whose primary field, supervisory, or administrative duties are the investigation, apprehension and detention of individuals suspected or convicted of violating the criminal laws of the United States. These employees are empowered with full law enforcement authority, as specified in Title 16 U.S.C. 1a-6 and 1b. Issuance of Type I commissions is authorized by a regional director or the Director.
5.1.2 Type II Commissions
These commissions are issued to temporary employees and those permanent employees whose duties are primarily law enforcement, and where park staffing and geographic considerations make it unfeasible to meet park law enforcement needs through any other redistribution of duties. Type II commissions are issued by park superintendents with the approval of the regional director or designee.
Persons issued Type II commissions may:
Carry and use firearms in the performance of duties.
Provide initial response to both misdemeanor and felony incidents. Initial response includes arrest, where appropriate.
Independently conduct investigations into misdemeanor violations.
Assist with investigations into felony violations.
Be deputized by other law enforcement organizations or entities where their Type II status is specifically acknowledged by the deputizing agency.
Persons issued Type II commissions may not (unless accompanied by a person with a type I commission):
Execute felony warrants as part of pre-planned operations (raids).
Conduct felony investigations.
Be detailed to "high risk" assignments outside of their park area unless approved by the regional director or designee.
Independently prosecute cases on behalf of the United States/NPS or serve as a park law enforcement specialist.
When not in duty status, commissioned employees within their jurisdiction may still exercise their law enforcement authority.