यदा वा प्रयातः कर्शयितुमुच्छेतुं वा शक्नुयादमित्रं तदा यायात् ॥ कZ_०९.१.४४ ॥
yadā vā prayātaḥ karśayitum ucchetuṃ vā śaknuyād amitraṃ tadā yāyāt
Or else, one should march only when—having marched—one would be able to wear down or uproot the enemy.
A capability-to-effect test: do not mobilize unless the operation can plausibly impose significant degradation or regime-level removal of the opponent’s power.