Whomever President Barack Obama taps to head the new Bureau of Consumer Financial Protection could find it difficult to keep ahead of the credit-card industry.

The Credit Card Accountability Responsibility and Disclosure Act of 2009, known as the Card Act, was intended to reshape the contours of consumer finance. Among other things, it forces card issuers to give customers more notice about interest-rate increases and restricts certain controversial billing practices such as inactivity fees.

Yet...