From the DCCC (partisan barking removed):
The House of Representatives voted yesterday 416-0 to ban misleading fundraising letters disguised as 2010 Census forms.
The National Republican Congressional Committee (NRCC) and the Republican National Committee (RNC) recently sent out political fundraising letters that looked like U.S. Census letters.
The Census Bureau was concerned that these misleading mailings would undermine response rates for the official census forms, which arrive in mailboxes next week. By misleading and confusing Americans about which forms to return, lower mail response rates of census forms increase government costs because a census employee is sent to every home that does not respond by mail.
The US Census estimates every one percent decrease in the mail response rate costs taxpayers approximately $85 million to send census workers back to re-count.