1. Aren't the elections conducted by states, not the fedgov?
2. California has a high percent of illegal residents. However I have never seen a credible study, showing that democrats win elections due to those people voting illegally.
Have you seen any credible evidence that they don't vote illegally? Without a proof of citizenship or even ID requirement, anyone can register and vote. In fact, in California people can register themselves many times using different names and no one would ever know or care.
I was a Democrat operative in California for 6 years and I know how they run voter registration drives. They send people out to the Mexican areas and pay them a buck for every Democrat they can register. If someone asks if citizenship is required, they are told to go ahead and register, and if there is a problem then they'll be notified. Of course, they are never notified because there is no mechanism for checking to see if the person registering is a felon, illegal, or whatever. These registrars camp out in front of the Catholic Churches on Sunday, the shopping centers, etc. They are specifically paid for Democrat registrations, so they tend to pick areas with high minority concentration. I knew of households in some of the Assembly districts I worked in that had 10 or more separate "voters" registered.
You can also bet the Farm Workers Union is making sure that everyone on their rolls is registered, citizen or not.