All actual money collected goes into the general treasury to be used as needed for all government expenses.

Now how the accounting is done by different administrations is another story. They aren't fooling anyone with their juggled bookkeeping. And there you have a point.

Despite the dire prediction in the OP there will be surpluses. Hopefully for a long, long time. Let's see what the retiring boomer generation and the crappy economy does to the so called surplus.