Procedural law is a broad term that deals with the rules that the court, lawyers, and parties must follow to properly try a case. In short, procedural laws deal with dates, times, numbers, and other procedural aspects of case that must be met in order for the case to proceed according to the law. Procedural laws are important because they afford parties due process of law under the U.S. Constitution. Due process essentially requires the government to treat individuals fairly under the law.

Procedural laws can be broken down into 2 main areas: (i) criminal, and (ii) civil. In other words, criminal procedural laws are different than civil procedural laws. Procedural laws differ depending on whether a case is tried in federal court or state court. Then, procedural laws differ from jurisdiction to jurisdiction and court to court.

Let’s go over an example to clarify how this operates.

Assume that Johnny files a complaint against his City for refusing to allow him to speak with a loudspeaker at a local public park during business hours. Johnny files his complaint in federal court because he’s concerned with his First Amendment freedom of speech rights. Johnny’s lawsuit is a civil action (as opposed to a criminal action). So, the federal rules of civil procedure will apply to Johnny’s case. The federal rules of civil procedure set the base for how procedural law works in federal courts. But particular federal courts are free to add "local rules" that do not conflict with the general federal rules of civil procedure.

So, depending on where Johnny lives, such as New York, Alabama, California, or Hawaii, and the court and judge to which the case is assigned, Johnny will have to follow any additional "local rules" for that particular court. In other words, this is one example of how procedural rules can vary from court to court.

As another example, in federal court a party can only submit 25 interrogatories (i.e. questions) to the opposing side in a civil case. However, many state courts allow more interrogatories, such as 40. Again, this shows how different procedural rules apply in different courts.

As another more basic example, think of procedural laws like ingredients in a recipe. For example, if you’re making an omelet, you’ll need basic ingredients such as eggs, green peppers, onions, mushrooms, ham, cheese, etc. You’ll also likely use butter to grease the pan and a good non-stick frying pan to cook the omelet. However, you can change the ingredients and tools you use to cook the omelet to get different types of omelet – i.e. different outcomes. For example, you might use only egg whites to create an egg white omelet.

In a similar way to cooking, procedural rules in different courts generally have many of the same rules with certain variations. However, these variations in the law can change the outcome of a case – kind of like how different ingredients can change the type of omelet.

Further, different procedural rules will sometimes dictate how a case is handled and the tactics behind how to most effectively prepare a case. This is called case management – just like a pro golfer manages a golf course and sets up differently for different courses. In the same way, lawyers must establish a "game plan" based on the court’s procedural rules.

With all that said, state courts have different rules than federal courts, and each particular state court is also free to add local rules that do not conflict with the U.S. Constitution or that state’s constitution. If this sounds like a lot of different rules to remember and a little confusing, don’t worry too much about it. That’s why lawyers go to school for three years, practice in particular jurisdictions, and take many additional years to study and understand the nuances of the court systems in which they practice.

Keep 3 keys in mind from all of this: (i) procedural laws essentially deal with the rules of the court, (ii) effect how a case is conducted, and (iii) are different than substantive laws. Please read substantive law for further details on that subject.