The revenue lost to Social Security, about $120 billion in 2011 due to the temporary tax cut, will be reimbursed to the Trust Fund from income tax withholding, over two years, not one. That means that with annual deficit spending already at $1.5 trillion, in a shut down there's even less cash flow to count on if $5 billion in funds are being siphoned off for this purpose monthly.
TheHill.com explains here:
The tax cut will put roughly $120 billion into workers’ pockets. Perhaps $90 billion of this, or three quarters, will be spent. This could provide enough of a boost to GDP to create more than 300,000 jobs.
Also, the Social Security trust fund will be reimbursed for the lost revenue. Under the deal that President Obama worked out with the Republican leadership, funds from general revenue will replace the lost tax revenue for the next two years. This means that the tax break will have no effect on the long-term solvency of Social Security.
Doh!
