I would agree it is within the letter of the law. The problem is: No one has defined the crime. Normally you'd have the crime defined and then the proceeding would determine whether or not the crime was actually committed. In this case, the proceeding is to determine if a crime has been committed. That's why its more a witch hunt.
This isn't a criminal court though. I don't think the house has to agree on a crime until articles of impeachment are filed. After all, you don't indict anyone until the evidence is gathered to make a case in the real world. In any case, the crimes here are requesting an in kind campaign donation from a foreign power and now bribery/quid pro quo.
