Current debt total (~$36T). At $100k per BTC, it would take 360,000,000 BTC to pay for it. At $4.7M, however, the gov still needs 7.6M BTC (over a third if the supply) to pay off the debt. The U.S will probably never control more than 20% of the network, however, in which case, the price of each coin will need to be ~8.6M per coin. Assuming (and it's a pretty safe assumptio that the debt continues to rise as the US gov accumulates bitcoin, the price will need to be still higher. I think if they act now on a strategic plan to purchase 4.2M BTC, when BTC is $13-15M, the country may be debt free. That price assumes a market cap of $273 - $315T. All assets in the world are likely $400 - 500T, so... still some room to grow if they act now! https://www.pgpf.org/national-debt-clock/