@Cycloptichorn,
Yes, it does point to future large unfunded expenditures. However it does add something to the argument when you examine it.
Yes, the US will eventually have to tax enough to pay back those trust funds as the bill comes due. This leads us to another point about the argument of when the trust funds go bust.
If the government is capable of paying the money back for the trust fund then they are taking in enough money to cover the shortfall when the imaginary money in the funds run out.
Let me see if I can make it simple
For 10 years -
The government takes in $100 and spends $100 but borrows $50 from a trust fund. The deficit is zero but the debt is $50 per year.
Over 10 years the government would have a debt of $500.
Over the next 10 years the government takes in $150 and spends $150 but $50 of what it spends is what was promised in the trust fund.
At the end of those 10 years, the trust fund is now owed no money but..
The government is taking in $150 so it could still pay out $50 for the trust fund shortage and $100 for the rest of its spending.
What I am trying to illustrate is that trust funds aren't going to suddenly force large increases in taxation when they are no longer owed money. Those tax increases will have to come before then to balance the budget.