For the Fed, the nearest parallel may be an oil price shock caused by some geopolitical event, such as those that took place in the 1970s, or a food price spike caused by a drought. What those events have in common is that they are caused not by economic fundamentals — such as when oil prices rise because the global economy is booming — but by some external shock. They are bad for growth, yet inflationary.

In those cases, monetary policy orthodoxy tends to emphasize looking past a one-time bump in inflation caused by the shock, while paying more attention to whether higher prices — whether for oil or corn or aluminum — are leading people to expect continually rising prices. A couple of years ago, with the Fed struggling to achieve the 2 percent inflation level it targets and with prices consistently rising more slowly, that might have been welcome.

Now, though, the Fed is pretty much achieving its inflation goal already, and with the unemployment rate at a very low level by historical standards, there’s reason to think higher prices may be on the way soon even before the impact of tariffs. In projections released at the mid-June policy meeting, the median Fed official expected that inflation would be 2.1 percent this year and next.

That calculus could change if a trade war starts doing major damage to the financial system, such as by causing steep losses in stock and bond markets or by causing financial stress for banks. But while the stock market is down a bit in recent weeks as the war of words over trade has escalated, so far the pain from trade wars has been limited to specific companies and their workers and customers. It has not been a systemic crisis.

For the last 11 years, from the housing downturn in 2007 that turned into the global financial crisis in 2008 and a prolonged, sluggish expansion after that, the Fed’s tools were reasonably well suited to the challenges that presented themselves. The central bank became even more central than usual to every economic discussion.

But this time, the economic risks are different, and if conflict over trade practices starts to cause damage to the broader economy, we shouldn’t count on the Fed to bail us out.