A protracted, escalating cycle of trade tensions has begun. In the latest action, the United States has proposed a 10 percent tariff on $200 billion in Chinese goods. This follows a tariff on $50 billion of imports from China. Together, the value of targeted goods amounts to nearly half of all American imports from China last year, and countermeasures by China are expected.

Even if all the proposed actions don’t go into effect, prolonged uncertainty alone can have a measurable impact on economic growth, and we should not underestimate the risks.

Most of the Federal Reserve’s policymakers agree that uncertainty and risks from trade policy have “intensified,” according to the minutes of the Fed’s Federal Open Market Committee meeting in June. Most private-sector economists share this view. While I don’t expect today’s conflict to be as severe as the Smoot-Hawley Tariff Act of 1930, which was meant to protect American workers but instead prolonged the Great Depression, it is unlikely that the global economy will escape these trade disputes unscathed.

Estimating the magnitude of the impact can be tricky. Consider this: Just the threat of trade actions, even if there is no follow-through, is enough to dent business sentiment and investment. Most business decisions are based on a five-year horizon. That means you need to be able to predict what you can charge for your product, and what it will cost to make it. Trade disputes provide a murky lens at best, which most likely delays investment.