If you can't get 2/3 of the senate to convict, impeachment is so much political theater. Democrats will be quite lucky to take a majority in the senate, 67 is theoretically possible but not realistic, I don't think, and unless a lot changes quickly there won't be many republican defections. Not that it's useless, because impeachment proceedings are another time sink for the executive branch, but it's foolish to put eggs into that basket because it's a broken mechanism.

The more important function of Congress over the next two years will be the stoppage of rubber stamping of Trump-friendly legislation, subpoenaing executive officials and forcing them to choose between testifying under oath and risking contempt (and public reporting of same, for whatever that's worth), and investigating and reporting on the crimes that Trump and his administration have committed over the past two years.