I’ve always thought the best defense against terrorism was an informed, calm public, in fact an informed calm public is exactly what the terrorists don’t want, they want terror. Some governments actually perpetuate the terror as do media who follow the adage if it bleeds it leads. I think so far the US government and US media have done an abysmal job of keeping people informed or calm.
In 1939 the British Ministry of Information commissioned some posters to be made as essentially a little propaganda as war was breaking out, it may have been pretty light on information but it does convey something that is worth remembering, “keep calm and carry on”.
And of course one person has made this into a t-shirt
I particularly like this blue one, but the brown with pink lettering is also very nice.