[a fool in paradise]

Use an official government seal in that watermark.

That way if they forge the watermark there are even more charges for the production and unused blanks.

[ProtectOurFreedom]

Every state should adopt all of the security measures used in the $100 bill. There is an excellent description of modern anti-counterfeiting at:

Detecting Counterfeit Money.

Scroll down to Steps 2 to 7: watermark, security strip, micro printing, color shifting ink, raised printing, and 3D Security Ribbon. If these are economical enough for bills, they should be used in ballots.

The cost of the communists stealing the 2016 election is billions of times higher than all counterfeiting combined. How do you put a price on hyperinflation, the loss of freedom, the communists enslaving all of us, re-education, gulags, and the loss of Western Civilization?