Well let's start where my last diary ended up: Debt Toolkit: Public, Subject to the Limit, Social Security Trust Fund and put those tools to work starting from the same screen shot from Treasury's Debt to the Penny web application.
Since Trust Fund assets are over half of Intragovernmental Holdings and those Holdings are included in Debt Subject to the Limit it follows that ANY increase in Trust Fund assets puts pressure on the Debt Limit. Now Trust Fund assets grow in any year where income from all sources, including interest credited to the existing TF assets, exceeds current cost. For example in 2011 Social Security operations on a combined basis were as shown in this linked Table from the 2012 Social Security Report: Table III.A3.—Operations of the Combined OASI and DI Trust Funds, Calendar Year 2011 The literal top line shows cumulative assets of $2.608 (fixed typo) trillion as of Dec 31, 2010, the bottom line $2.678 trillion on Dec 31, 2011. This difference of $69 billion in assets added directly to Intragovernmental Holdings and so directly into Total Public Debt Outstanding and Debt Subject to the Limit.
Now it is a fact that this increase in assets is net of interest credited, on a cash flow basis Social Security was actually negative as a portion of the $114 billion in interest earned on existing Trust Fund assets had to be paid in the form of cash. Now one can argue whether this is a problem for taxpayers or not, after all the money comes from somewhere, but for the purposes of deficit and debt scoring that cash flow fact is irrelevant. In 2011 Social Security ran a surplus of $69 billion which subtracted directly from the unified budget deficit. At the same time that $69 billion flowed right to the bottom line of Total Public Debt. Meaning that as regards Social Security the common sense idea that debt is simply the sum of deficits is totally reversed. Social Security surpluses add to debt and don't subtract from it.
And of course the reverse is true. If you want to reduce the pressure exerted by Intragovernmental Holdings on Debt Subject to the Limit you would want to REDUCE Trust Fund Assets. And given that growth in those assets is directly the result of income from all sources exceeding cost, the only way to reduce that growth is to either cut income or increase benefits. Which leads to the rather astonishing result that over the short run and in specific regards to Debt Limit calculations proposals to means test Social Security and/or impose a new COLA formula via Chained-CPI are arithmetically COUNTERPRODUCTIVE, they tend to put pressure on the Debt Limit and not relieve it.
Now this doesn't mean that it is totally irresponsible to address long term solvency issues in Social Security, but dragging them into a specific debate over the Debt Limit is pure blackmail, the 'solutions' the Republicans are demanding have literally less than zero to do with the vehicle which they are using to demand them. Now it is not true (as some supporters would have it) that Social Security has no effect on deficits or in our case debt, because it does. But in ways that go against 'common sense'.
Cutting Social Security cost does less than zero to reduce either short term or long term Public Debt, instead any such cuts either increase that Public Debt or in some formulations (which personally I don't agree with, but are pushed by people smarter than me) leave it unchanged on net.
On the other hand Social Security benefit cuts or alternately revenue increases do serve to reduce so called unfunded liability. But unfunded liability is not debt. And for that matter is not legally a liability. Instead it is a purely theoretical calculation of the Present Value of the gap between Scheduled and Payable benefits under Social Security, something I discussed in my diary from Monday Social Security Rashomon: an Actuary, a Defender and a Reformer Meet
Now I am perfectly happy to talk for hours and days about Unfunded Liability over either the 75 year actuarial window or even over the (God Help Us) Infinite Future Horizon. Fun stuff!!! But neither that 'Liability' or that Horizon have any direct relevance to either 10 year budget windows or the current Debt Limit. And only fools or liars will tell you different. Or to summarize: House Republicans.