Q&A on the census and redistricting: Which states may gain or lose?

Political activists will be watching closely Tuesday when the Census Bureau releases the first official population data from the 2010 census.

The numbers, updated every 10 years, will break down the “resident population” of the U.S. and detail the new apportionment of seats in the House of Representatives, based on population shifts since the 2000 census. Some states are likely to lose seats and, hence, votes in Congress.

Why is this a big deal?

It can help determine who will control the House, state legislatures and even the presidency.

Tuesday’s release launches the process of redistricting, in which each state redraws congressional district boundaries to make each district roughly equal in population — in some cases giving one party a significant electoral advantage.

But the importance of reapportionment is not limited to House races. The number of seats assigned to each state can influence presidential contests because they are used to determine representation in the electoral college.

What should we be watching for on Tuesday?

The states with the biggest anticipated changes are Texas, which could gain as many as five seats, and Ohio, which could lose two. Nine states — Illinois, Iowa, Louisiana, Massachusetts, Michigan, Minnesota, New Jersey, New York and Pennsylvania — could each lose one.

It’s anticipated that California will keep its 53 seats and remain the largest delegation.

How could this affect a presidential contest?

Presidents are selected by a vote of the electoral college, and the makeup of that body is based partly on the number of seats a state has in the House of Representatives. It takes 270 electoral college votes to win the presidency, and the votes occasionally have been extremely close.

For example, in 2000, Republican George W. Bush received 271 electoral college votes to defeat his Democratic opponent, then-Vice President Al Gore.

Four swing states — Florida, Nevada, Iowa and Ohio — stand to gain or lose seats. A few of traditionally safe Democratic states could lose seats, and some traditionally safe Republican states could gain.

Which party is most likely to benefit from this process?

The Republican Party.

In part, that’s because the new population numbers are expected to increase representation in the Republican-leaning states of the South and West while traditional Democratic strongholds in the North are losing seats in the House.

Perhaps more important, Republicans will have far more control than Democrats over the redrawing of congressional district boundaries. Seven states have turned over redistricting to an independent commission. But in most states, legislatures control the process, and in last month’s election Republicans won big on the state level, gaining control of 20 legislative bodies.

tom.hamburger@latimes.com

kim.geiger@latimes.com