Wiktionary
preemptively
adv. in a preemptive manner
Usage examples of "preemptively".
Unspoken was the second part of that sentence--that if the Victor were carrying antisurface missiles, Batman would need to act preemptively, to take the submarine out before it could launch.
Alpha Two was only one step short of open hostilities, and ROE Baker authorized any squadron commander to open fire, even preemptively, if he believed his command was under threat.
For that matter, they might also believe that understating their true strength would cause us to feel less alarmed and so be less likely to act preemptively.