Answer:
National-security argument
Step-by-step explanation:
The United States imposing the trade restrictions on the steel rods because they are considering the national security argument. United states wants to improve the domestic production of steel rods. When there is no restrictions on the trade of steel rods then this will make the U.S. overdependent on the other countries.
So, they consider the situation of war in which there is a need of many weapons to defend. For making these weapons, there is a need of steel rods.
Therefore, the U.S. wants to become self dependent for steel rods.