This was largely to prevent war profiteering, though it lasted until 1964 when the top marginal tax rate was lowered to 70%. It's not really relevant to our times unless you're forecasting another global war, in which case all bets are off.
According to http://www.csmonitor.com/Business/new-economy/2011/1025/Iraq..., the Iraq war will wind up costing "more than the $3.6 trillion the US spent to fight World War II, even after adjusting for inflation". Add in Afghanistan and the ongoing airstrikes and likely expansion into other areas of extremism, and maybe we should start talking about Americans at home paying a bit for the militarism in the form of higher tax rates.
The weird thing seems to be that the people who are most anti-war want higher tax rates for things that are not war, and then when the money gets spent on war, they want even higher tax rates for the things they were originally promised but didn't get.
Looking at tax history it seems like a repeating game of bait and switch.