President Trump invoked his authority under Section 201 of the Trade Act of 1974 when he issued Proclamation 9693 on January 23, 2018, imposing safeguard tariffs on imported crystalline silicon photovoltaic cells and modules. The proclamation established a four-year declining tariff schedule, with duties beginning at 30 percent on both cells and modules in the first year and declining by 5 percentage points annually through 2021. This mechanism—a safeguard action rather than a retaliatory tariff—allowed the administration to frame the policy as protecting a domestic industry deemed vulnerable to import competition without requiring separate congressional approval.

The tariffs directly increased costs throughout the American solar supply chain. Installers of residential and commercial solar systems faced higher expenses for imported components, which represent a significant portion of total project costs. These increased expenses were passed along to consumers and businesses purchasing solar installations, effectively raising the price of renewable energy adoption during a period of expanding solar deployment. The tariffs also created regional disparities in their economic impact, with areas dependent on solar energy as a cost-effective electricity source experiencing particular pressure on electricity prices and renewable energy development timelines.

This action represents an early manifestation of Trump's broader protectionist trade agenda, one that would intensify significantly in subsequent years. The solar tariffs foreshadow the expansion of tariff authorities evident in later actions, including the continuation of national emergency declarations regarding trade deficits and the suspension of duty-free de minimis treatment for all countries—both mechanisms that broaden tariff applications across American commerce. These interconnected policies reflect a consistent approach to using executive trade authorities to impose costs on imported goods, regardless of broader economic consequences.

The tariffs faced immediate legal challenges from solar industry groups and trading partners, though courts largely upheld the administration's statutory authority under Section 201. The primary opposition emerged from industry advocates and state renewable energy programs rather than from sustained legislative action. Reversing the tariffs would require either congressional action or a new presidential determination that the safeguard measures were no longer necessary to facilitate positive adjustment in the domestic solar industry.