The president used his office and withheld aid to Ukraine (with Russia threatening their border) to get dirt on his opponent. From the Department of Justice: “An employee may not use his public office for his own private gain or for that of persons or organizations with which he is associated personally. An employee's position or title should not be used to coerce; to endorse any product, service or enterprise; or to give the appearance of governmental sanction. “. He then tried to cover it up and has obstructed all investigation into this matter. In other words, it’s wrong and worthy of impeachment and removal.