One of the nation's toughest immigration policies goes into effect in Prince William County (web|news) today, where police are now not only empowered but actually required to check the immigration status of every person they arrest: starting today, every person arrested in Prince William County will be run through a national database to check their citizenship status.

Prince William County's Board of County Supervisors unanimously passed the immigration crackdown last fall and the policy went into effect at the beginning of March, but officials returned to revise it almost immediately. The changes to the policy were approved in late April.

» Check the latest on this issue from the Prince William County web site here.

The initial measure allowed police to check immigration status on the basis of probable cause, but did not require it for every arrest. That approach came under fire because its subjective standards opened the door to racial profiling.

In addition to the required citizenship check, the revised policy allows police to question a suspect before an arrest if the individual's ID is suspected to be fake, and orders that no one be arrested solely to determine citizenship or immigration status.

The Prince William county police chief says that the 500-member police force has been trained in the implementation of this new policy and is ready to use it effectively.