State and local governments to have a balanced budget and prepare for economic downturnsThe restriction of having to balance the budget keeps the country (like individuals) from overspending, the absence of a balanced budget enables congress to fund pet projects and black ops without the intense scrutiny of the public and finally having a balanced budget will diminish and eventually remove the huge deficit hanging over the country.
Countries, like people, tend to overspend when restrictions are removed. It's human nature. By not enforcing a balanced budget hard decisions are not made and never will be made. Politicians will take the easy road and cater to whatever will get them elected. They will not be forced to make difficult decisions and therefore will not make them. They will leave them to the next guy who will do the same until disaster overcomes us. The guidelines of balancing the budget serve as boundaries and force people and nations to make difficult choices, choices that would never be made if those restrictions weren't there.

Not having a balanced budget enables politicians and agencies to hide money. Because every penny is not accounted for, waste is rampant and fraud all too common. Moreover pet projects like studying the wild platypus in the Antarctic are funded while veterans benefits may be cut. Having a balanced budget causes every penny to be accounted for and cuts down on waste and fraud.
And finally not having a balanced budget contributes to the enormous deficit, which will in turn cause steep tax rates in order to pay for the deficit, which in turn will cause slavery. By that I mean that people will have to work more and more for less and less and eventually will be working at levels that will not be enough to live on. Some people are already working 3 and 4 jobs just to live. Moreover, as tax rates rise business is squelched. Businesses cannot make decent profits, thereby either taking their businesses off-shore or going out of business completely. As the deficit grows larger and larger our economy becomes more and more at risk of collapsing completely. This in turn will cause social strife and possibly the threat of civil or international war as the younger generation will be forced to carry more and more of the tax burden while benefiting less and less and the risk of defaulting with our creditors looms.
All of this is not only possible but inevitable if we do not balance the budget.