Never. In order for the President of the United States to mention "bitcoin" before 2020, there must be a United States. When empires collapse, they also break apart. This grows more likely the older I get.
A mere 30 years after the collapse of the Soviet Union? Interesting.
I'm not the first to suggest such a possibility, and this is a long time coming. Also, there is no evidence in the historical record that suggests that a nation as large as the US is long-term sustainable, anyway. Texas even reserves the right to secede in their statehood documents, explicitly. California is still a larger economy than Texas, but based on land mass, population or/and economic size; Texas would be at least as qualified to be a nation unto itself as half of the nations of Europe.