Application, Counterarguments, Conclusion
Once you have completed your discussion of all legal authority relevant to your issue statement, you then must explain how your facts fit in with the existing law. Your goal here is to return to and resolve the issue you raised in the issue statement. In this section, you predict (in a law office memo), or argue for (in a brief to court), a particular resolution of your facts by the court. Here you recount those facts that are relevant to the issue statement and the subsequent rule/rule proof section.
A good application section weaves the cases into your facts. Language from the cases should be prominent and woven into your discussion of these facts. In the rule proof you discuss cases to support the rule statement. In the application section you might draw analogies or contrasts between the existing cases and your facts as a way to reach your conclusion. (NOTE: if you mention the holding, reasoning, or facts of a case in the application, you should first introduce these aspects of the case in the rule proof; do not use the application section to introduce new case discussion.)
The use of a counterargument is a good way to convey that the existing legal authority is not clear, unequivocal, or unified when applied to facts like yours. It may be the case that you cannot predict with certainty the outcome of your case, given your facts. There may be competing lines of authority, competing policy rationales, and/or a dearth of cases on point in your jurisdiction. Use of counterarguments is also an effective way to address, and then dispose of, the perspectives of those with whom you differ.
Counterarguments function differently in predictive and persuasive writing. In a law office memorandum, identifying counterarguments helps your client assess the strength of a legal position, the availability of defenses to a claim, and alternative ways of analyzing a situation. In persuasive writing such as a brief to a court, counterarguments address and dispose of likely arguments that the opposing side will advance. In advocacy, treatment of counterarguments typically is briefer and more conclusory than in a law office memorandum because the purpose of including them is to limit, distinguish, or neutralize arguments that your opponent has marshaled.
The conclusion is a short statement of your position on the question or issue explored in a given IRAC/CRRACC. Your application section should be written in a way that leads the reader inexorably to your conclusion. Likewise, the conclusion statement at the end of the discussion should contain language that refers to the application section. It should read as the natural concluding statement of your application section.
In your application section you may have struggled with areas of uncertainty in the legal doctrine and/or competing policy rationales. You may have also grappled with a seemingly contradictory assortment of facts: some seem to fit into the requirements of the rule; others suggest that the rule is not satisfied. You may have weighed arguments against counterarguments. After you have done all this, you must take a position and make a statement about how the court will/should apply the law.
As a legal writer, it helps to have an assortment of qualifiers to acknowledge how certain or uncertain you are of the actual judicial outcome. Your conclusion can convey that your argument in that IRAC/CRRACC is a slam-dunk — you are completely confident the court will rule the same way — or that the outcome is really a toss-up and could go either way. Or you can convey any level of confidence in between. Keep in mind that the reader will be judging your credibility as a legal thinker based on (among other things) the congruity of your tone with the data at hand.