"...concluding that 750 to 800 votes cast were invalid,..."

Invalid might be for many reasons. It does not prove anything specific about why.

Everyone knows that the driving force behind some of these laws and claims IS racially motivated. Even when a law or precaution is needed, many of those who want it are only vaguely concerned with the general welfare.
What we are concerned with is how to have laws and practices that can't easily be used to harass decent, legal citizens. No one can really think of how to check on those who are already in this country illegally. Cracking down on employers might help...and finding better ways to allow LEGAL temporary workers will also....but many want to come here and 'melt into' the regular population and not even try to go home again. Some are criminals....but many are just poor, out-of-work folks looking for a better life.
   
The fact that this country was built by immigration is only marginally relevant these days....we don't NEED everyone who thinks they might like come here.