If we impeach everyone who violates the Constitution in the slightest, we'll have no one to fight for us. Even our Founding Fathers ran into legality issues from time to time. If we looked close enough at even the best Presidents this country had, we'd still find unConstitutionality problems.
You don't win a war by executing your generals.
Find these words for me in the Constitution:
Education
Entitlement
Social Security
Medicare
Foreign aid
Where is the authority to restrict firearms? Free speech?
None of these things are minor infractions. At what point would you start 'executing the generals'? If you show the political will and moral courage to shoot execute the first one, it won't happen again so soon.