Should the administration lose the Supreme Court case, it might shift to product-specific tariffs. This transition could introduce short-term market volatility, as the administration might initially propose high tariff levels as a negotiating tactic before settling on lower, more palatable rates.

A Supreme Court loss on using one specific law (IEPA) for tariffs would not end the administration's ability to wage a trade war. The executive branch has other laws it can use to impose levies, such as those allowing temporary or retaliatory tariffs, limiting but not eliminating its power.

To address voter concerns about affordability, the administration may pivot on seemingly unrelated policies like trade. A potential Supreme Court ruling limiting presidential tariff authority could be framed as an opportunity to pursue a lighter-touch tariff policy, alleviating cost pressures exacerbated by the AI buildout.

The legal theory previously used to strike down some of President Biden's policies is now being applied to Donald Trump's tariffs. The Court argues that for economically significant actions, the president needs explicit congressional authorization, which the 1977 law cited lacks.

Even if the Supreme Court rules against the administration, it may not change U.S. tariff levels. The executive branch has alternative legal authorities, like Section 301, that it can use to maintain the same tariffs, making a court defeat less of a market-moving event than it appears.

Stocks most affected by tariffs showed a muted reaction to a pending Supreme Court decision. This suggests investors believe the executive branch could use other authorities to maintain tariffs and that any potential refunds from an overturn would take years to materialize, diminishing the news's immediate market impact.

While the base case is that the President would replace tariffs struck down by the Supreme Court, there's a growing possibility he won't. The administration could use the ruling as a politically convenient way to reduce tariffs and address voter concerns about affordability without appearing to back down on trade policy.

Even if the Supreme Court rules against using emergency powers (IEPA) for tariffs, the President can use a patchwork of other legal authorities like Sections 122, 232, and 301. While this would curtail the ability to impose tariffs on a whim, it would still allow the administration to replicate the revenue effects.

If tariffs are reduced following a court ruling, companies will experience immediate cost relief. However, these savings are passed to consumers slowly, over two to three quarters. This delay creates a temporary tailwind for corporate profit margins before prices on the shelf fall.