http://www.banknoteden.com/Legal%20Tender.htm

That is a wonderful write up of the various "notes" and the ramifications of each on the DEBT.

"So, great. But what do these obligations mean? Well, remember that these notes were actual U. S. debt issued by the US Treasury. Therefore, at certain times, restrictions on their use were deemed necessary to avoid the treasury to default. Acceptance of U. S. notes issued by the treasury for interest on its debt (which includes these notes) would be silly. They wanted notes which were backed by other banks or government agencies, like the Federal Reserve." from the above link.

The converse is also true, the surrender of "lawful money" from the FED reserve "lawful money" back to the treasury would directly effect the debt. This is why I have an issue with the IRS sending refunds to redeemers (not an issue with that per se) my issue is that the IRS

might not be letting the treasury know we are redeeming lawful money and reducing the amount of goods and services pledged to the Federal Reserve.