Byron York of the Washington Examiner contends congressional Democrats are preparing for the “ultimate fishing expedition.”

Yes, Democrats want to start a new investigation into already-under-investigation Trump-Russia allegations. And yes, they want to investigate Trump associates like Michael Cohen, Roger Stone, and others. But by far the biggest thing Democrats want, now that they have the majority in the House, is to get their hands on the president’s tax returns.

House Democrats want to use a 1924 law that allows any one of three entities — the House Ways & Means Committee, the Senate Finance Committee, or the Joint Committee on Taxation — to demand that the Treasury Department turn over the returns of any individual. Passed in the wake of the Teapot Dome scandal and controversy over the finances of Treasury Secretary Andrew Mellon, the law has almost never been used. For the first 50 years of the law’s existence, no one tried to get a president’s returns — although the law played a role in the fight over Richard Nixon’s finances — and in the years since Gerald Ford took office, presidents have voluntarily made their returns public. Until Donald Trump.

So now, Democrats propose that the entity they fully control — the Ways & Means Committee — force Treasury, parent agency of the Internal Revenue Service, to turn over the president’s returns. What do they hope to find? What is remarkable is that even the most aggressive Democrats don’t seem to have a clear idea what they will find in the returns. They’re just sure there must be something bad in there.