But every so often, the time comes when the threat is so great, the situation has gone so horribly wrong, that there is no proportionate response. When circumstances are so dire as to justify the use of any and every thing that might solve it, no matter how reckless, nonsensical, or horrific, regardless of cost. When even the summoning of Godzilla, king of the monsters and patron saint of collateral damage, could not possibly make the crisis any worse. Every so often, the situation crosses the Godzilla Threshold.

https://tvtropes.org/pmwiki/pmwiki.php/Main/GodzillaThreshold