Do Zombies Get The Franchise?
I think the most important question to answer is whether zombies get to vote. Until we figure that out, no other policy implications will matter, because based on sheer numbers alone, zombies represent a potent voting block.
It won't take long for pandering Congresspeople to realize how easy it would be to appeal to these single-issue voters. I predict that if zombies do get the vote, we'll quickly see the rise of the "Eat People" party, which would legalize the consumption of human flesh (excep for the flesh of members of the House and Senate).
The Eat People party would never have to resort to gerrymandering because zombie hordes would inevitably swamp polling places and voting booths. And candidates wouldn't even have to bother raising money. You don't need TV and radio ads when your voter base is a swarm of insatiable undead, who will relentlessly convert new party members with every bite.