I must have -- but enough states are opting out that it won't matter, and if it ever affects the outcome of a presidential election, I'd expect the losing candidate to go to SCOTUS. The constitution establishes the electoral college, not a popular vote system, and the laws might be challengeable on those grounds.
But yes, a popular vote means those votes won't matter. There will no longer be battleground states -- merely a national election (which was never designed -- it was stated many times that what was being created was a federal government, not a national one), in which the states with the largest populations rule everyone else.