A Federal Reserve official suggested Wednesday that the U.S. economy might have permanently slowed, which means low interest rates might be the norm for a long time in the U.S.

Charles Evans, the president of the Federal Reserve Bank of Chicago, said a higher Federal Reserve target for short-term interest rates might not be warranted, given the circumstances.

His argument, made in an outline for a speech to be delivered in Beijing, is effectively at odds with the view expressed by Fed leadership last week that the Fed might be justified in raising interest rates twice this year. Raising the target would influence interest rates throughout the economy, on corporate loans, mortgages, credit cards, and more, and could add some economic uncertainty to the election if done before November.

Evans said, however, that there are "good arguments for believing that we are in for a protracted period of low equilibrium real interest rates."

He cited conversations with long-term investors and insurers who are making plans based around the expectation that interest rates will remain low.

Part of the expectation that interest rates will remain low is the fear that economic growth won't necessarily pick up. "Something fundamental is going on," Evans remarked, positing that the slow growth might be the result of demographic change or a slowdown in productivity.

Also, interest rates might be kept down because of enormous demand from around the world for safe assets like U.S. Treasury securities, Evans mentioned.

Evans is not a voting member of the Federal Reserve's monetary policy committee this year. In the past, however, his ideas have shaped the Fed's decisions. In late 2012, the Fed adopted his idea that it should promise not to raise interest rates from zero until unemployment fell to 6.5 percent, a strategy that became known as the "Evans Rule."