This method assigns seats in the House of Representatives according to a "priority" value. The priority value is determined by multiplying the population of a state by a "multiplier."
For example, following Census 2000, each of the 50 states was given one seat out of the current total of 435. The next, or 51st seat, went to the state with the highest priority value and thus became that state's second seat. This continued until all 435 seats had been assigned to a state.Essentially, there is a formula to compute the "multiplier values" for each each State's potential seats. These values are then multiplied by each State's total population, thus creating a "priority value" for each potential seat per State. These values are then tabulated from largest to smallest and seats are then assigned by going in order, from highest priority value to lowest, until all remaining slots are filled. Here is a table of the priority values from the 2010 Apportionment. As can be seen, the first seat on the list--the 51st, after every State gets its initial one--goes to California, the 52nd goes to Texas, the 53rd to California again, and so on. Obviously, the States with the largest populations begin to pile up seats early.
We can think of the process in this way: each assignment theoretically lowers the population of each State by the averages population per seat (which happens to be 710,767 persons per seat for 2010). Thus, priority values for all States move towards the same point as the largest States fill out their delegate count. States with very low populations will have the lowest priority values as a matter of course. It's an effective system and, in my opinion, quite fair. Here are the results of the 2010 Apportionment. The far right column shows the change in number of seats, losses or gains. For since the total number of Representatives remains fixed at 435, any gain by one State--due to population growth--must be offset by a loss to another State.
In 2010, the biggest gains were for Texas (+4 seats) and Florida (+2 seats). Arizona, Georgia, Nevada, South Carolina, Utah, and Washington all gained one seat as well, for a total of 12 seats picked up. So, there had to be a loss of 12 seats among the remaining States. The biggest losses were for New York and Ohio, each of which lost two seats. Eight other States lost one seat: Illinois, Iowa, Louisiana, Massachusetts, Michigan, Missouri, New Jersey, and Pennsylvania.
Apportionment is not given a great deal of attention, even though it is a very important thing. Looking at the changes in 2010, one can't help but see them in relation to the Tea Party-induced Republican wave of victories in the 2010 Mid-Term Elections. Most of the States that gained seats were either consistently "red" States, or were States with strong Tea Party movements. Losses were mostly for Northeastern States and States with large metropolises hard hit by a weak economy.
But apportionment also affects Presidential Elections, since it is also the basis for allotting Electoral Votes. The impact on the 2012 Elections was as follows:
Of the eight States that picked up seats, five were won by Romney, resulting in an additional eight electoral votes that he would not have had in 2008. Of twelve states that lost seats, two were won by Romney, meaning two fewer electoral votes, a net gain of six votes. On the other side, Obama picked up an additional four electoral votes from States that gained seats but lost ten electoral votes from the States that lost seats, a net loss of six votes. Imagining that there had been no changes to seats in 2010, Obama would have won the 2012 Election by a slightly wider margin, 338 Electoral Votes for him, 200 for Romney.
Obviously, the ultimate impact here was inconsequential, due to Obama's margin of victory. Yet, if we imagine that Romney won Virginia, Florida, Nevada, and Ohio (a fantasy, as it turned out), he would have won the election, 272 Electoral Votes (Romney) to 266 Electoral Votes (Obama). However, if the Apportionment of 2010 had not occurred, the totals would have been different. Romney would have had eight fewer Electoral Votes, Obama would have had eight more: 264 Electoral votes for Romney, 274 Electoral Votes for Obama (in 2008 Apportionment numbers). Thus, Obama would have won, even if Romney had been more successful in the "swing" States.
This is all a thought exercise, to be sure, but it points to the significance of Apportionment and what that means for the future. The U.S. Department of the Interior has an excellent chart that shows the pattern of shifting numbers in Apportionment from 1900 to 2000:
The numbers in the bars represent percentages of House seats assigned to each region. The shifts are obvious: a growing South and West, as compared to a shrinking Northeast and Midwest. But here's something to consider: in every Apportionment since 1900, California has gained at least two additional seats, until 2000 when it gained just one and 2010 when it gained...none. Most of the gains for the West were fueled largely by a booming California in the past. Not so in 2000 or--obviously--2010. Now, the growth in the West is in Arizona, Nevada, Utah, and Washington. The Northeast continues to decline, as does the Midwest. The South's share continues to increase. 2010 numbers will show an even higher percentage there, thanks mostly to Texas and Florida.
The shrinking electoral importance of New York cannot be understated, either. As recently as 1960, it had the most Representatives--and most Electoral Votes--of any State. Now, it has fallen behind both Texas and California and is, in fact, equaled by Florida. In 1960, Georgia and North Carolina combined had 21 seats, 20 seats fewer than New York's 41. Both have since creeped up steadily, now with a combined total of 27 seats, equal to New York's current total. Throw in South Carolina and Florida and the Southern seaboard has a total of 61 seats, while New York, New Jersey, Connecticut, Rhode Island, and Massachusetts have a total of 55. In 1960 the total would have been 39 and 76, respectively. It's a staggering reversal of importance, both in the House and the Electoral College
The point is, those States most solidly in the "blue" column are going the wrong way or stagnating, when it comes to Apportionment, while States increasing in their apportioned seats are--for the most part--"red" or "swing" States. Future Presidential races are going to look less and less like those of the past forty years, during which time it has been accepted dogma that California and the Northeast were the most critical regions, that a candidate's ability to secure both put that candidate in the catbird's seat. Bush won elections in 2000 and 2004 without winning either areas and consequently those elections were exceedingly close.
Obama won in 2012, it is true. But as I showed above, the 2010 Apportionment opened a new window for a Republican victory without the Northeast and California, one that would have been closed in 2008 and even moreso in 2004. 2020 is a long way off, yet not so long. The next Apportionment--given the already extant trends in the nation--will likely follow that of 2010. California may potentially lose seats for the first time ever. There is no reason to believe growth in Texas and Florida will not continue, meaning New York will fall to the number four slot, all by itself. The road to the White House may very well begin and end in the Sunshine State and its close neighbors like the Carolinas and Georgia. This is not your father's Oldsmobile.