The Anti Cybersquatting Consumer Protection Act ACPA allows a trademark owner to bring a lawsuit against a domain registrant, when:

1. The registrant has bad faith intent to profit from the trademark.
2. The domains is confusingly similar to the trademark.

ACPA occurs in court and can result in civil fines. Whereas UDRP is an arbitration process that can, in the worst case for the registrant, result only in losing the domain.

On a humorous note, ACPA also stands for "American Concrete Pavement Association" and "American College Personnel Association", among others.