What key limitation does the SRUF impose on the use of force?

The correct answer highlights a fundamental principle of the Standing Rules for the Use of Force (SRUF), which emphasizes that the use of force must be both necessary and proportionate. This means that any application of force should be carefully considered and carried out only when it is essential to achieve a legitimate military objective. Additionally, the level of force applied must not exceed what is necessary to deal with a specific threat or situation.

This principle is crucial for maintaining ethical conduct and ensuring compliance with international humanitarian law. It seeks to minimize harm and protect non-combatants, reinforcing the idea that military action should always strive to be balanced, avoiding excessive use of force that can lead to unnecessary suffering or escalation of conflict.

The other choices, while touching on aspects of military engagement, do not align with the SRUF's emphasis on restraint and proportionality. They could potentially lead to scenarios where the use of force becomes arbitrary or unchecked, which is counter to the intent of maintaining disciplined and lawful military operations.