Governments can NEVER EVER pay off the national debt because the amount of money in circulation: the money supply, is controlled by the banks (the Fed, JP Morgan, et al). The banks will always ensure that there is never enough money in circulation - at any given time - to pay off the national debt.
The banks create money by issuing loans. Over 90% of all currency in circulation - at any given time - consists of this 'bank money' which: to you and me, should really be called 'debt money'. When a loan is agreed - the sum agreed to is called, 'the principal'. Under the fractional reserve banking system 90% of this money can then be loaned out whilst 10% must be held in reserve.
Say a bank agrees a loan of 10,000 dollars. Once agreed this amount becomes 'new money'. As things stand the banks can now loan out 9,000 dollars of this 10,000 principal. Once the 9,000 dollar loan is agreed to this becomes 'new money and the process repeats. The original 10,000 dollar eventually leads to the creation of almost 100,000 dollars worth of 'new money'. All new money is debt. When governments bailed out the banks in 2008 they essentially nationalized all the 'toxic debt' accrued by fraudulent banking practices (the sub-prime scandal).
So what are you going to pay off the national debt with? More debt?
In case you haven't noticed the amount of money in circulation is rapidly contracting. This is a deliberate policy of the banks. They simply call in old loans and refuse to issue new ones. They will even refuse to issue new loans after they are given billions of dollars in taxpayers money by Ben Bananke.
Every American President that has understood the problem and gone on to try and fix it by constituting a national bank with the monopoly power to issue currency has been assassinated: including Kennedy and Garfield.
You do not live in a democracy. The national debt will never be paid off and there is nothing that you or your government can do about it.