In order to institutionalize this compromise solution, a series of increasingly
elaborated non-binding model conventions (MCs) were drafted,
which could be used as templates for bilateral double tax treaties (DTTs).
The MC refers to a series of legal constructs establishing a nexus between
the transnational tax base and a country (Bird andWilkie, 2000: 91–95). For
example, the concept of a permanent establishment (PE) codifies what is
taxable as a separate entity of anMNE in the source country. The important
point about this and other constructs, still in use today, is that internationally
defined rules are kept to aminimum. TheMC and the bilateral treaties
based on it provide general guidelines (although these can be quite complex
in order to ensure universal applicability) about the nexus between a
person or an entity and the respective jurisdiction. Bilateral DTTs achieve
no more (nor less) than disentangling the transnational tax base and assigning
it to different jurisdictions. Once the jurisdiction to tax has been
established, a country is then free to apply its own national tax law to its
share of the income. This approach is not aimed at harmonizing national
tax laws; the internal qualities of national tax systems are not subject to
the regime rules. The DTA regime merely regulates the interfaces of autonomous
national tax systems and, in consequence, governments retain
almost unlimited sovereignty over their share of the transnational tax base
(Li, 2003: 31; Vann, 1991: 102).