Final answer:
The protection of an infant industry is a valid argument for protectionism and is considered true; however, its successful implementation can be challenging.
Step-by-step explanation:
The protection of an infant industry is recognized by economists as a valid argument in favor of protectionism, which is true. The infant industry argument suggests that new industries may need to be shielded from foreign competition via subsidies or trade restrictions until they can compete on their own. Evidence has shown that this strategy has been successful in certain regions like East Asia. However, it is also noted that implementation can be quite difficult, with the risk that protected industries fail to mature and the temporary protection policies become permanent.