This week's release of the 2010 census report on the makeup of the U.S. population contained some potentially good news for Republicans. Population shifts from the Northeast and Midwest to the South and West are expected to help Republicans in Congress.
One of the reasons for the U.S. census every ten years is to determine population shifts among the 50 states. That information is then used as the basis for shifting congressional seats among the states that lose and gain residents.
Under the U.S. Constitution, each state has two U.S. senators and at least one member of the House of Representatives. But membership of the 435 member House is based on population, with heavily populated states receiving more congressional seats than less populated states. For example, California, the most populous state in the nation, has 53 House seats, while Wyoming – the smallest state in terms of population – has only one House seat.
William Frey is a demographer with the Brookings Institution here in Washington.
"And the idea is to count where everyone is, so that when those states send representatives to Congress, the numbers of representatives are more or less proportional to the people who are in those states – to give everyone an equal say in the Congress," Frey said.
The 2010 census shows that Americans continue to move away from the Northeast and Midwest toward states in the South and West. Because of the population shifts, 18 states will gain or lose House seats by the 2012 elections.
Texas is the big political winner in this year's census and will gain four House seats. Florida will gain two. Other states gaining one seat include Arizona, Georgia, Nevada, South Carolina and Utah. Most of those states tend to support Republicans, so political experts say Republicans will likely gain from the added seats, at least in the short term.
Many of the states losing seats tend to favor Democrats.
Amy Walter is political director for ABC News.
"There are some experts who are looking at this data and saying that based on what they see now, Republicans could add 10 more seats to their total," said Walter.
The redrawing of congressional districts to accommodate the census results is done by state legislatures and governors in the various states. Republican gains in last month's midterm elections at the gubernatorial and state legislative levels will strengthen their hand in the redistricting process that will begin next year.
This year's census showing continued movement to the South and West is a continuation of a trend that has been occurring for decades, says demographer William Frey.
"Since 1970, there has been a big shift in the congressional representation toward the South and West and away from the Northeast and Midwest," Frey added. "I think the states that are likely to gain the most people are the ones that are not as strongly favorable to the Democratic Party or even to President [Barack] Obama as places that are losing population."
The shift in House seats might also an affect the Electoral College voting for president. Under the Constitution, the number of electoral votes each state has is based on its total number of House and Senate seats.
Shifting some House seats to Republican-leaning states in the South and West might help the Republican presidential candidate in 2012.
Tim Storey is an expert on congressional redistricting at the National Conference of State Legislatures. He spoke to the C-SPAN public affairs television network.
"Those numbers are not only used for representation in the U.S. House, but the Electoral College votes are based on those numbers as well," Storey said. "So this also has an impact on the 2012 presidential election and the number of electoral votes that states will have in the presidential election."
The census report shows that Hispanics are a major reason for population growth in states like Texas, Arizona and Florida – a trend, experts say, that might help Democrats in the long term.
Hispanic American voters tend to vote Democratic, but Republicans also value their support and that makes them a growing and highly-sought constituency by both major political parties in the years ahead.