Sorry but in times of war, the regular "proof beyond reasonable doubt" cannot apply anymore, or you lose said war.
If you declare war without there being a bona fide casus belli, you'll be whisked out of power so fast your head will spin. See e.g. https://en.wikipedia.org/wiki/2024_South_Korean_martial_law_...
If you don't declare war, you don't get those emergency powers. You only get peacetime powers.
Russia loves to go right up to the line, and then cross it a little bit, just to antagonise you. But unless you're willing to be the instigator of WW3, you'll stick to peacetime powers and peacetime courts with peacetime standards of evidence
Clearly this will need to change somewhat, if the other side wants to engage in hybrid war tactics. Nothing new, Cold War was a thing.
Do you want to make your country such a nightmare country, so you can also cheat like they do?
But when dealing with an outside state-level aggressor, I want my country to be be a cunning, hypocritical, powerful strongman.
The distinction under what mode a certain event should be treated should be pretty straightforward and can be determined using democratic means, e.g. a normal judge ruling "I rule this cable cutting incident to be an act of state-sponsored aggression against our democracy" (which would allow the alphabet agencies, special ops etc to "do their thing" with no repercussions whatsoever.)
for example:
1) a murder happens between a husband and wife, two normies, after lengthy, normal court proceedings the proof who did it is not 100% conclusive, accused person goes free
2) a murder of an anti-russian political dissident happens, a russian ex speznas officer is caught in relation to the event -> he "disappears" one day and the case is closed
I believe this is the only way to "win" this cold war.
Sadly, it seems a fiction.
You'd better start advocating for freedom and democracy rather than using cynicism. If you don't, who will? Democracy is you; nobody is going to fix what you destroy.
Cynicism is a tool for peacetime, a way of keeping things honest (maybe not the most effective way, but it has an effect). But when there is serious threat - when your platoon is facing the enemy - cynicism is a failure of duty to your team.
Also, am I on the hook because my wife's great-grandfather was russian?
The other thing that sprang to mind was the US interning their own citizens in camps. Would you be in favour of internment camps across Europe for all citizens with any Russian heritage, preemptively locking them up in case they might provide succor to The Enemy?
You're standing in a forest, lighting a forest fire to kill the other guy. There is lots of history about this most fundamental error.