Patent protection in the South: Is there a case for nondiscrimination?

We evaluate in terms of equilibrium world welfare the principle of national treatment (NT) in Southern patent protection. We use a variety-expansion model with R&D in North and South, and with Southern imitation targeted at both foreign and domestic innovations. In the short-run of Northern economy, NT can never dominate discrimination in the sense of generating a higher world welfare, and it tends to be dominated by discrimination. In the long-run of Northern economy, we obtain three results. First, under free trade, NT is favorable to the North while discrimination is favorable to the South. Second, if the entry cost of Northern R&D market is high and the strength of protection for Northern innovation under discrimination is not that weak, then NT is strictly dominated by discrimination, no matter whether trade barriers exist or not. Third, if trade barriers are sufficiently large, then NT dominates discrimination only when the strength of protection for Northern innovation under discrimination is weak; otherwise, NT is strictly dominated by discrimination.