I wish Voter Fraud got taken as seriously as audited financial statements. The standard for that is quite a low barrier:

A material weakness is a deficiency, or a combination of deficiencies, in internal control over financial reporting, such that there is a reasonable possibility that a material misstatement of the company's annual or interim financial statements will not be prevented or detected on a timely basis.

Mail in votes is just another way to reduce controls in place in a system that is already lacking on controls.