Tom Swiss's New Lie

Republican Tom Swiss is remarkable.  Bad enough that he's running an agressive campaign of misinformation and deceit regarding the fact that he's a Republican and not a Democrat.  But now, in seeking in the nomination for the Democratic Party, he's sent out this mailer about his opponent:

"Smith will not be able to hold office."  That's false. Tom Swiss knows its false. I think that's the definition of a lie.

I'm not defending Smith -- I only know the allegations - against him.  He could be proven guilty he might not.  But our system presumes innocence.  UNLESS Smith is proven guilty, he can hold office.  Tom Swiss has already convicted Smith.  The fact is, he's not been convicted of anything.

Its hard to understand why there isn't at least some restraint on this point.  Pointing out the facts would seem to be enough even for a Republican running an under-the-rader campaign of deceit posing as a Democrat.  Why lie and deceive?