The mid-1850s were years of economic boom, which gave way to a slump at the end of the decade. To maintain railway construction, the ongoing rebuilding of French cities and to counter economic malaise, government spending on public works rose. The regime also sought to stimulate the economy through fiscal reform; a trade treaty with Britain in 1860 formed part of a programme intended to reduce taxes and streamline the state. Affairs abroad, though, complicated this agenda. Profiting from the destabilisation of the international order that followed the Crimean War, France intervened militarily in support of Italian unification, while simultaneously seeking greater prestige through a policy of all-out global interventionism in the Middle and Far East and Mexico. The costs of interventionism abroad, combined with ongoing expenses in Algeria and on public works, eroded the regime’s latitude to lower taxes, straining the legitimacy of the fiscal system. Meanwhile, defeat in Mexico added to this discontent, producing a crisis of the fiscal-military system, which weakened the regime, easing its collapse in 1870 during the Franco-Prussian War.