Money does not so much cross borders as it transcends them, performing as if national boundaries had no significance. Language, culture and political ideology are also transcended. Inadvertently, capital flows have become a global unifying force. The decoupling of money and national identity. National currency is now decoupled with geographic space.
Currencies can circulate as easily outside a country as inside.
Under uncertainty, a foreign currency can virtually displace a local one as the country's legal tender. The 1990's witnessed the dollarization of whole economies in Latin America, Eastern Europe and the Soviet Union. The decoupling of development and public debt. Later, private banks made loans, but the borrowers were still governments or public agencies. The 1900's witnessed diversification of development funding to include private capital flows, which now dominate.