The Constitution defines impeachment at the federal level and limits impeachment to "The President, Vice President, and all civil officers of the United States" who may be impeached and removed only for "treason, bribery, or other high crimes and misdemeanors".[32]
Several commentators have suggested that Congress alone may decide for itself what constitutes a "high crime or misdemeanor", especially since Nixon v. United States stated that the Supreme Court did not have the authority to determine whether the Senate properly "tried" a defendant.[33]
In 1970, then-House Minority Leader Gerald R. Ford defined the criterion as he saw it: "An impeachable offense is whatever a majority of the House of Representatives considers it to be at a given moment in history."[34]
Again, do you really think the Democrats are worried about what kind of charges they are going to file on impeachment? The charges are just an inconvenience.