Democratic Sen. Mary Landrieu is under pressure from most of Louisiana's congressional delegation to support Republican Sen. David Vitter's legislation requiring that next year's census forms ask about the status of a person's citizenship.

Supporters of the amendment fear Louisiana will lose a congressional seat to a state with high numbers of illegal immigrants if the citizenship question is not included. Census officials say most of the forms have been printed and that nobody complained when the wording of the questionnaires was made available last year.

Rep. John Fleming of Shreveport urged Landrieu's support of the amendment in a letter Tuesday, joined by Reps. Rodney Alexander, Charles Boustany, Bill Cassidy, Charlie Melancon and Steve Scalise.