Here’s what will happen. The current trend is for the population of the center of the country to move towards the coasts. Gradually, the power of the inner states, as far as in the Senate and in the electoral college will be concentrated in the hands of people who represent far fewer people.
This power will help them block the political efforts of the vast majority of people, unless they can extract payments in return, such as greater farm subsidies, or higher prices for natural resources.
Eventually, the populace coastal areas will get tired of this. They will try to get a constitutional amendment to change the Senate and Electoral College to proportional representation. They will never get the majority needed to put the amendment to the states, and even if they did, they would never get the super majority needed in the states to make the change. So the less populace states would keep their power.
Finally, the coastal areas would get sick of this, and they would place an embargo on the inner states. The inner states would get supplies from Canada and Mexico, so the coastal areas would have a problem. On some pretext, perhaps evading the embargo, the coastal states would attack the border regions of Mexico, and take it over. Then, Canada would get the message, and close the Northern border.
Things would be tense for a while, and then the central states would start sending suicide bombers into the major urban areas of the coastal states. The coastal states wouldn’t stand for this, and they would attack, using the armed services. As this happens, the armed services will split with the central states servicemen defecting (and taking hardware with them) to the central states. Because the central states provide vastly more servicement than the coastal states, the central states would have a much stronger military power, but the coastal states have the people and the industrial capacity. Eventually, they will win, subduing the central states, making membership in fundamentalist Christian Churches a crime, and imposing atheism everywhere.
The underground Christians would continue to organize and terrorize the coastal populations with suicide bombs, but things would settle into an uneasy detente, until people erupted again, this time, ironically, with the “freedom fighters” of the central states allied with Mexico and the central American states, and thus would ensue the next world war.
Cool, huh?