When Bush was elected, there was a discussion about the philosophy of US president election. The president is the president of the united states, and not the president of a single giant state.
US is a federation and therefore, difference of size between states tend to be erased.
The constitution allow states to divided them (but in this case it's an obvious joke, no texan will want division) but not allow that the US president is direclty elected by US people.
Direct election will make sense, but will be a big constitutional change that will recquire the positive votes of all states to be effective. Such a vote could lead to a new secession in US
