In terms of balancing the budget, there’s no way to answer that question—no mathematical basis for declaring either spending or revenues the problem. Sure, the 2010 federal budget would have been balanced if the government had cut spending by $1.293 trillion to equal its revenues of $2.163 trillion. But it would have been just as balanced if the government had increased revenues by $1.293 trillion to cover its total expenditures of $3.456 trillion.
What we can say is that over the last 40 years, government revenues have kept pace with economic growth while government spending has run steadily ahead of it. If you look at federal finances from the dawn of the Great Society in 1965 to the beginning of the Great Recession in 2008 (see the chart below), you’ll notice that Gross Domestic Product and federal revenues, both expressed in per-capita terms and adjusted for inflation, were about two and a half times as large at the end of the period as at the beginning. Federal expenditures were three times as large.