Federal Reserve Chairman Jerome Powell’s first six months on the job were smooth sailing. The past six have been the opposite.
He has learned that the economic outlook can change suddenly, that communicating with jittery markets is harder than it looks and that President Trump isn’t likely to make his job any easier.
Looking ahead, Mr. Powell will have to apply what he’s learning to a question that could define his term—whether to cut interest rates at coming meetings to keep the economy growing.
The Fed chairman is navigating three discrete challenges: setting a policy to extend what is already a 10-year-old expansion,

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