The messaging system is orthogonal to the trust relationship between banks in different countries. In the old days, this trust came from family bonds, e.g. the

The messaging system is orthogonal to the trust relationship between banks in different countries. In the old days, this trust came from family bonds, e.g. the various arms of the Fuggers or the Rothschilds. Nowadays, it's... more complicated. The US government spent billions on making foreign banks like BNP Paribas whole on contracts they had with AIG because it could not bail Goldman Sachs without also bailing them out, at least not without destroying the basis of trust in the international financial system. That's the part where compliance, risk management and AML-KYC intervenes, along with government employees installed directly inside the key banks to monitor it.