Don't confuse debt and deficit. The value of government securities, whether you are speaking of the ones that the SS funds are in or simple savings bonds, certainly adds to the national debt. Debt is simply the amount owed on these securities, including interest. That debt cannot be retired unless the budget has a surplus.   We used to have one, but the Bush II administration spent it on off-budget wars and the recession that we are currently (slowly) climbing out of compounded the problem.   If the overall budget is in deficit, meaning that spending is in excess of income received, than certainly the interest on these securities adds to the deficit, since that interest is a line item in the Federal budget.

The problem has two possible solutions - cut Federal spending or increase overall tax revenues. I suppose that spending cuts are possible, but as a former Federal employee and knowing how tight resources are, I doubt that is practical. Putting tax rates back to where they were before the Bush II cuts would certainly help; putting them back to where they were before the Clinton cuts would be even better.