If you consider the latter years of his presidency, as well as his immediate post-presidency retirement, it'd be more accurate to say:

"Ronald Reagen was probably innocent by way of Alzheimers"

A lot of people who met him during the last two years of his presidency described what we now know to be early symptoms of Alzheimers. He also came out publicly as having it not 5 years after leaving office.

You can, and you would be gravely mistaken.