If this happens, chances are high that nations will be dragging who will hold more because no one wants to be left behind. Imagine what this will do to the price of a Bitcoin.
When the US made the announcement on allocating part of their treasury into Bitcoin for a long period no nation responded to it. Trust me when I say most nations still do not believe in Bitcoin, regardless of the news surrounding it and the interest of the Americans some nations would rather sit and watch everything play out. And one good reason they will remain adamant is that they don't have the same economic strength as the US in terms of finance to the US is far above them. Only countries with valued currency can stand to buy Bitocin without any melting down of the economy.
Other nations aren't always as transparent as the United States on certain issues. It is quite possible that many nations already have clandestine Bitcoin stacking operations. It would almost be foolish not to. Only the United States is so massive with so much economic power that they don't need to resort to stacking in secret. They can just print as much as they want to buy as much as they want and not care about the market effects. I'd guess there are probably a couple dozen nations already stacking BTC. I am personally aware of executives at the largest companies in the world who have been stacking for many years. For example, it is only a matter of time before Apple embraces Bitcoin...