A new report from the Center for Immigration Studies points out a peculiar effect illegal immigration is having on congressional apportionment. Although illegals can't vote, their tendency to settle in cluster areas raises population counts in certain congressional districts. When those districts are reapportioned every 10 years, they gain in political power -- even though they contain fewer bona fide voters or legal residents.

Here are some highlights of the report:

• Census data reveal that 31 congressional seats shifted from one state to another in 1990, or will do so in the next census.

• Thirteen of those were or will be reallocated because of immigration -- with four destined to change because of illegal residents.

• Fifteen million immigrants have entered the country legally since 1980, and 75 percent of all immigrants live in just six states.

California is the biggest winner in redistricting. Between the results of 1990 and 2000, it will gain a total of nine seats due to immigration.

The report says that although congressional districts are supposed to be roughly equal in population -- with an average of 570,000 people each in 1990 -- heavily concentrated immigration means it now takes far fewer votes to elect a representative in certain jurisdictions because so many of the residents are non-citizens.

In the 1996 elections, for example, the number of votes sufficient to elect a representative in some districts of California and Texas was only about one-quarter of the number needed in the average Michigan district.

Source: William Branigan, "Study Says Immigration Skews Congressional Apportionment," Washington Post, October 6, 1998.