Preemption

Preemption

What is preemption?

In the American system of government (i.e. federalism) there are multiple levels of government. At the top is the United States Federal Government, followed by state/territory governments, and then finally with municipal government at the most local level. Power generally gets more limited as you get more local, with the federal government having the most power with the fewest restrictions and municipal governments being the most restricted. This is preemption- the concept that if a law or rule from a higher level of government either explicitly or implicitly preempts lower levels of government, those lower levels are prohibited from passing their own rules about that topic. Preemption places one of the most significant boundaries on the powers of home-rule municipalities, as those municipalities are still limited by state and federal preemption. Dillon’s rule municipalities do not need to worry about preemption as they are only able to legislate where there is explicit authorization to do so.

Explicit vs. Implicit Preemption

Explicit preemption is when, for example, a state law explicitly states that no municipality may legislate on that issue. An example of explicit preemption is 18 Pa.C.S. § 6120 which provides that “No county, municipality or township may in any manner regulate the lawful ownership, possession, transfer or transportation of firearms, ammunition or ammunition components when carried or transported for purposes not prohibited by the laws of this Commonwealth.”

Implicit preemption is more nuanced and requires more legal interpretation. One type of implicit preemption is referred to as conflict preemption and holds that if a local ordinance “irreconcilably conflicts” with a state law, the local ordinance will be found to be invalid.^[1] The logic of this preemption is pretty straightforward- if it is impossible to be in line with both laws at the same time, the state law wins and the local law is not allowed because it prevents the state law from being fully realized. Municipalities can generally pass laws that are more stringent than their state counterparts. The PA Supreme Court found that there was no conflict preemption when Adams Township passed a zoning law that required a minimum of 1,000 ft setback for mining activities because the state law required a setback of 300 ft, so the local ordinance did not prevent the state law from being followed.^[2] 

The other type of implicit preemption is called field preemption. Field preemption refers to a situation in which the state (or federal) government has passed enough laws about a topic that it can be implied that that legislature had the intent to be the only voice on the field at issue. For example, it has been consistently upheld that the General Assembly has field preemption over all regulation of public utilities, despite no mention of preemption in Title 66 of the PA Code which includes all regulation of public utilities.^[3]