For decades, the size of the U.S. House of Representatives has pitted state against state in a fight for political power after each census.
That's because, for the most part, there is a number that has not changed for more than a century — the 435 seats for the House's voting members.
While the House did temporarily add two seats after Alaska and Hawaii became states in 1959, a law passed in 1929 has set up that de facto cap to representation.
It has meant that once a decade, states have had to face the prospect of joining a list of winners and losers after those House seats are reshuffled based on how the states' latest census population counts rank. How those seats are reassigned also plays a key role in presidential elections. Each state's share of Electoral College votes is determined by adding its number of House seats to its two Senate seats.
For most of the House's history, however, states did not lose representation after the national head count's results were released. Generally speaking, as the country's census numbers grew, so did the size of the House since it was first established at 65 seats by the Constitution before the first U.S. count in 1790.
At the country's founding, many framers were concerned that the original House was "way too small," according to Yale University law professor Akhil Reed Amar.
"This might seem esoteric today, but you got to remember that the Constitution is the product of an American revolution. And that revolution was all about a key idea — no taxation without representation," says Amar, author of the upcoming book The Words That Made Us: America's Constitutional Conversation, 1760-1840. "If you're going to have big-time taxation and anemic representation, people are going to say, 'Wait a minute. We want to be taxed by people who know us, who look like us, who understand the concerns of their constituents in their districts.' "
After the 1840 census — and in one of the last decades before the 14th Amendment ended the census's counting of an enslaved person as "three fifths'' of a free person — Congress did drop the number of House seats from 242 to 232. The latest census numbers showed an increase compared with the 1830 results, but Congress could only agree on a smaller House size after Senate pushback over increasing the number of seats.
"And then it went back up and resumed the growth process again," says census historian Margo Anderson, author of The American Census: A Social History.
There's nothing at all magical about the number 435 Congress settled on.Dan Bouk, associate professor of history at Colgate University
That growth plateaued after the 1920 census, when Congress, for the first time in history, did not pass a new law about how to use the results of the latest national tally to reshape the House.
"The apportionment system failed," explains Dan Bouk, an associate professor of history at Colgate University who has written a new report for the research institute Data & Society about how lawmakers in the 1920s ultimately shaped the House's current size.
Some congressional leaders at the time pushed to leave it at 435 seats, the size it had grown into after Arizona and New Mexico joined the union in 1912.
"The thing that really caused the apportionment to get hung up over and over again throughout the 1920s was the insistence of a set of leaders that the House of Representatives could no longer grow any larger," Bouk says. "They said it's about efficiency. They didn't want to pay for more office space, to pay for more Congress people and more clerks. They believed the House couldn't be a deliberative body if it grew any larger."
While those kinds of arguments against making the House bigger were not new, they won out in 1929, when Congress passed the law that set up an automatic process for reapportioning the House based on the existing number of seats.
"There's nothing at all magical about the number 435 Congress settled on," Bouk adds.
In fact, there has been discussion over the decades about expanding the House, which would require Congress to pass a new law. But Bouk notes that the system for automatically redistributing 435 House seats after each census has created "a kind of inertia that makes such changes very unlikely."
Still, Anderson, the census historian, says she's concerned about how representative the House actually is at this unchanging size. A century ago, there was one member for about every 200,000 people, and today, there's one for about every 700,000.
"Congress has the authority to deal with this anytime," Anderson says. "It doesn't have to be right at the census."
And it might have to if, for example, Washington, D.C., or Puerto Rico becomes a state.
Until then, there will still be a fight for the power in 435.