(for people who don’t know the origin, it’s from the IRA: https://en.wikipedia.org/wiki/Brighton_hotel_bombing#IRA_sta...)

The quote is a pithy formulation of Blotto game theory, or "front analysis" [0] which I've taught in cybersecurity for some years now as an introductory concept alongside Dolev-Yeo [1]. It is obliquely connected to the "attackers advantage" (here as a business concept [2]) and "terrorists always win in the end".

As the number of fronts to defend grows, in space or time, the uncertainty of how to allocate resources against novel attacks becomes overwhelming, as does the burden of hyper-vigilance. The enemy can afford to sleep and wait.

Security is an essentially conservative project. One is defending existing resources, rights, powers... against an opportunistic insurgent. Security of democracy (as Franklin said, "if you can keep it") against tyrants (who are simply "terrorists" in waiting) is no different.

[0] https://en.wikipedia.org/wiki/Blotto_game

[1] https://en.wikipedia.org/wiki/Dolev%E2%80%93Yao_model

[2] https://www.goodreads.com/book/show/21413841-the-attacker-s-...

Ironically, Thatcher was in fact lucky every time and they never ended up being lucky at all.