Final answer:
Economists may conditionally support tariffs when used to counteract unfair trade practices like dumping or currency manipulation, as these measures can protect domestic industries. They might also endorse temporary protection for infant industries that could later gain a comparative advantage.
Step-by-step explanation:
Among the scenarios provided, economists may offer conditional support for tariffs and quotas when they are strategically employed to counteract unfair trade practices such as dumping or currency manipulation by trading partners. Specifically, option 2 — when a country becomes convinced that its trading partners are engaging in dumping or currency manipulation — can justify the implementation of tariffs or quotas to level the playing field and protect domestic industries from these unfair competitive advantages.
Another instance drawing some support is option 5 — when, with temporary protection, an infant industry could emerge and show long-run comparative advantages over other countries. This protectionist measure aligns with the concept of nurturing domestic industries until they become competitive internationally, at which point safeguards may be removed, potentially leading to net economic benefits.
Protectionism, through tariffs and quotas, raises domestic prices and limits choice for consumers. However, it benefits domestic producers by protecting them from foreign competition and can be retaliatory if other nations engage in unfair trade practices.