There are a few obstacles to over come ... First Trump has to do something impeachable... Then the Democrats have to have a majority in the house to impeach him for it. It would be a lot easier if the Democrats controlled the house, they don't right now... Then it goes to the senate who hears the evidence and if it agrees it removes him from office. It would be a big help if the Democrats controlled the senate, they don't right now.
So it seems to me that the Democrats first have to take over both the house and senate. In 2018 24 senate Democrat seats are up with only 8 Republican seats. The Democrats have to keep all 24 they hold now and take at least 3 Republican seats. That means they have to prevail in 27 senate races while the Republicans only have to prevail in 6. (A tie is broken by the VP)
Michael Moore is blowing smoke up their butt. But if it makes Democrats happy, go for it.