The real investigation (Mueller's - forget about Little Devin's clown show) has been going for only ten months. You have no clue what evidence there is, but obstruction of justice is one that it would take a complete idiot not to see.
I agree, but imo obstruction of justice is pretty much a nothing burger unless there is an underlying Trump-Russia relationship that has some blackmail, or worse, potential. Unless there is something a relatively unbiased person would find alarming in that it should have been disclosed prior to Comey's Nov Surprise for Hillary, then a relatively unbiased person can say "Well, he wanted to shut down the investigation because it was leeching away at ability to enact an agenda.
And I know he doesn't have an agenda beyond a wall, but that's not the issue in Russiagate.