considering the major damage to this country that vote fraud has, does and will always produce, once convicted for any degree of vote fraud ought to carry a minimum of 20 years of hard labor in a federal prison. If you think that is cruel and unusual punishment, just consider all those who have given their lives and limbs to give and keep the right and freedom to even vote in this country. What these folks got can hardly be called punishment, let alone a deterrent to any future participation they may have in vote fraud.
Stiffer penitilies would simply make the criminal all the less likely to confess to his or his partners crimes.
Between secret ballots and fraud prone registration and actual voting rules. Enforcing electoral law is all but impossible, unless the ones breaking it become recklessly stupid & and all but admit to their crimes.