Is it considered illegal for nations to regulate or restrict trade with other nations?

Nations have the sovereign right to regulate or restrict trade as they see fit, including imposing tariffs, quotas, or embargoes. However, such actions may violate international trade agreements or treaties that a country has entered into, potentially leading to disputes in organizations like the World Trade Organization (WTO). While not inherently illegal, trade restrictions can be challenged on the grounds of fairness, legality, or compliance with international law. Ultimately, the legality of trade regulations depends on the specific context and agreements in place.