It's not about "3 large states"; it's about "the majority of the people" controlling the election. Right now, each voter in Wyoming is 3.5 times as powerful as a voter in California. In the 1770s, the proportion of largest state to smallest - of only thirteen states - was about 18:1. Now, California:Wyoming is about 66:1. Yet each state gets 2 senators, which is more than 3 times as unfair as it was at the time of the Constitution (66/18); plus each state is guaranteed a representative, but the number of representatives is capped at 435, so quantization error means that Wyoming's representative is shared by 568,300 while each representative in California is shared by 704,566. A little algebra, and Wyoming has 189,433 people per elector, while California has 678,945, which is where we get that 3.5 proportion.