A more thorough explanation:

The plaintiff's-viewpoint rule is a principle used by courts to determine the amount in controversy in a case. According to this rule, the court should only consider the amount of damages claimed by the plaintiff when measuring the amount in controversy.

For example, if a plaintiff sues a defendant for $50,000 in damages, the court will use this amount to determine if the case meets the minimum threshold for federal court jurisdiction. The court will not consider any counterclaims or defenses raised by the defendant when measuring the amount in controversy.

This rule is important because it ensures that plaintiffs have access to federal courts when their claims meet the minimum threshold for jurisdiction. It also prevents defendants from manipulating the amount in controversy by raising counterclaims or defenses that have no merit.