Tariffs as a Strategy Problem: How MBB Frames Supply Chain Disruption

Seventy-six percent of trade professionals now expect current US tariffs to be permanent, not cyclical. Bain published a dedicated piece titled "Tariffs: The Next Chapter" that frames this shift as a structural reset, not a political blip.

This matters for your interview prep because the case type has changed. Supply chain questions used to focus on efficiency and cost reduction. Now they layer in geopolitical constraint, which forces you to trade off resilience against margin in ways that pure optimization never required.

When a case prompt says "our client sources 80% of components from a single country that just triggered a 25% tariff," you are not solving a logistics problem. You are solving a strategy problem with a cost function at its center.

Imagine you are sorting a massive pile of mail into labeled bins. The rule is strict: every letter goes into exactly one bin, and no letter gets left on the floor. If a letter fits two bins, you created the wrong bins. If a type of letter never has a home, you missed something real. That sorting rule, applied to strategic ideas, is what MECE means: mutually exclusive, collectively exhaustive.

For a tariff disruption case, your top-level MECE split is: impact on cost structure vs. impact on strategic options. Do not collapse these. Cost structure covers margin compression, working capital changes, and landed cost per SKU. Strategic options cover what the client can actually do in response.

Inside strategic options, a clean second-level split is: sourcing geography, production structure, and commercial response. Each branch is a distinct lever. None overlap. Together they cover the full response space.

The cost function is where most candidates go shallow. They say "move production to Vietnam" without pricing the decision.

Think of it like comparing two mortgage offers. You would never just compare the interest rate. You would model total cost of ownership: closing costs, monthly payment, insurance, property tax, and your own liquidity across the full loan term. Sourcing decisions work the same way. The tariff rate is only the interest rate. The full cost includes retooling capital, lead time buffer inventory, quality ramp costs, and supplier risk premium.

For each sourcing alternative, build a landed cost model with four components: direct input cost, logistics and duties, transition cost amortized over three years, and a risk-adjusted margin for supply continuity. Compare those totals, not the tariff line item in isolation.

Bain's tariff framework explicitly segments clients by "trapped" vs. "flexible" supply chains. Trapped clients have long-term contracts or specialized tooling locked in one region. Flexible clients have modular production. Your cost model has to surface which one your client is before you recommend anything.

Practice this framework on a real case. The adidas-yeezy-2022 case on BoardroomIQ puts you in the room.

Make-vs-buy is the decision hiding inside almost every supply chain case, and tariffs force it to the surface faster than any other shock.

Here is the cleanest way to frame it. Ask three questions in order. First: does the activity drive competitive differentiation? If yes, bias toward making. If no, bias toward buying. Second: can an external supplier achieve equivalent or lower landed cost after tariffs? If yes, outsourcing becomes viable. Third: what is the switching cost if the geopolitical environment shifts again in 24 months? If switching cost is high, you are not just making a cost decision. You are making a commitment about where the client wants to be in 2028.

The recommendation almost always ends in one of three postures: concentrate and defend (double down on a single low-cost region and absorb the tariff), diversify (split production across two or more geographies, accepting higher unit cost for lower concentration risk), or relocate (exit the tariff-exposed region entirely). Frame your recommendation explicitly in one of these three. Vague answers about "balancing cost and risk" do not land in final rounds.

The candidates who perform best on supply chain cases have stress-tested their frameworks before the interview room. Here is how to build that muscle in the next six weeks.

Build a landed cost model from scratch. Pick any product with a public bill of materials, assume a 25% tariff on the primary component, and model the landed cost for three alternative sourcing geographies. Do not stop at unit cost. Include transition cost and lead time inventory.

Run the MECE drill on a live headline. Find a current news story about a tariff-exposed company. Build a two-level issue tree on paper in under ten minutes. Check it for overlap and gaps before reading any analyst commentary.

Practice the make-vs-buy recommendation out loud. State a posture, state the single most important assumption that makes it right, and state the single assumption that would flip your answer. Do this in 90 seconds. If you cannot do it in 90 seconds, your logic is not tight enough yet.

The best way to practice tariff strategy is under realistic pressure, with a case that fights back.