Sometimes a metaphor is the best way of explaining things...
When DC got slammed this week with the worst blizzard(s) ever, the sentiment was decidedly in favor of officials mustering every possible resource in order to clear the roads and restore power to those who lost it.
Nobody said: We don't have enough money in the budget to deal with this problem, so we're going to wait for the snow to melt! Going over budget in this case, is the RIGHT THING TO DO, because inaction would simply allow a dangerous situation to get worse.
In this real-life situation there is a lesson for those who either don't understand, or want to explain why the government has to spend gobs of money in order to help get us out of this recession. If there was no spending by the "spender of last resort" the economy would potentially fall into a dangerous death spiral. Going "over budget" (ie. increasing the deficit) in this case is the prudent thing to do... just like deploying the plows and paying huge amounts of overtime is the thing to do as the mid-Atlantic digs out from the most snow its seen in a loooong time!