NO!  There must be a legible postmark to validate that a ballot was received by the deadline.  And the MUST be a deadline....we can't just count til 'whenever'.....

Voting is already as easy as it can be.  You have WEEKS to vote now, not just the day of or with a relatively restricted absentee ballot.  You can mail it, you can drop it off, you can go in person even now, 40+ days before the election.  NOBODY is disenfranchised and there MUST be some minimal requirements to be met, like a legible postmark!