“My preference on tax reform is that it be revenue neutral,” the Senate majority leader Mitch McConnell told reporters this week.

Another big plank underneath the idea that Mr. Trump’s economic policy will be stimulative is an expectation that he will embrace a large-scale infrastructure spending package.

But while the president-elect mentioned that idea in his election victory speech, he hasn’t put much meat on the bones of the plan since. The details matter a great deal for how much an infrastructure plan could lift growth. For example, tax credits that make the finances of building toll roads more favorable are less likely to create a huge boost in activity than spending on upgrading physical infrastructure outright.

So on both tax cuts and infrastructure, there’s no guarantee that the actual scale of stimulus will match some of the early postelection talk. Economists at JPMorgan Chase, for example, are forecasting economic growth of just under 2 percent for both 2017 and 2018 — about the same as the pace of the last six years.

And that’s before you factor in the risk that some elements of Trump economic policy could end up being a drag on growth. Think of a trade war with China or Mexico, immigration restrictions that limit the supply of labor or geopolitical disputes.

All that gives the Fed every reason to take a wait-and-see approach to shaping its policy. If the Trump economy really starts to take off, the Fed could move more aggressively to raise rates. But it will do that based on actual evidence and data rather than the president-elect’s rhetoric.

If Trump’s Fed Governors Choose to Keep Rates Low

Which leads to the other scenario, in which the economy accelerates at the risk of overheating. History is littered with examples of politicians in that circumstance pressuring their central banks to keep rates low to encourage growth.