Counties across the nation have begun to quantify the impact of a new federal law that will, in effect, turn counties and cities into tax collectors for the federal government. And some of the early estimates are staggering.

Section 511 of the Tax Increase Prevention and Reconciliation Act would require local governments that spend more than $100 million annually to withhold 3 percent of their payments to most vendors and contractors. President George W. Bush signed the bill into law, but it does not take effect until 2011.

For full text, visit the National Association of Counties web site.