Simple. When a mass war is declared on your nation (3 enemy nations declaring on you) a war tax rate is unlocked for the defender. 55% Income tax rate for the 7 day duration of the war. This is only fair!
One reason I joined this edition was because I do not favor the 24 hour waiting period between nation updates. I was shocked to discover this is the same in TE. It is an outrage. TE should update every 12 hours.