Even though public hearings on the impeachment of U.S. President Donald Trump have just begun, the subject has already become encrusted with legends and myths on all sides. In a polarized country, each side has its own talking points — and isn't paying enough attention to the other side to know when those points are based on errors. So far, three stand out.

Take White House acting chief of staff Mick Mulvaney's famous remark that Trump's critics should "get over it." This was widely taken to be a brazen statement that it was fine for Trump to use foreign policy to seek to harm his political opponents. But that's not what Mulvaney was saying. Nor was CNN accurate in reporting, "Mulvaney confirmed the existence of a quid pro quo and offered this retort: 'Get over it.'"

Mulvaney's press conference was on Oct. 17. He mentioned news accounts about the previous day's testimony from a former State Department adviser, Michael McKinley. Those reports said that McKinley had quit because he was, as the Associated Press put it, "disturbed by the politicization of foreign policy."