From Barry Ritholtz:
Unfunded Tax "Cuts": You will note that the I have the word “Cuts” in quotes. Why? To quote Milton Friedman, “When is a tax cut not a tax cut? When the so-called tax cut is accompanied by a larger rise in government spending than in prices.” In other words, all unfunded tax cuts — including these — are actually future tax increases on the next generation.
You mean there's interest on that borrowed money? Read the whole post for more.