deterrence is a funny thing. on some level it is just... vibes. an actor won't do a thing because it fears the consequences.
but it is also very real. a lot of ink has been spilled about what the west is deterred from vis a vis ukraine, but deterrence is causing arguably bigger issues for russia:
despite knowing where all the logistical hubs are for ukraine military assistance, russia is deterred from striking them. russia has also been deterred from using wmd in ukraine (please please don't say tear gas), and from a forceful response to arrival of more/better western weapons