With a stroke of his pen Friday afternoon, President Obama cemented a political victory by reining in a credit card industry widely condemned for snaring consumers in financially crippling traps.

When the new law takes full effect next February, card issuers will no longer be able to impose sky-high penalty interest rates on customers whose payments arrive a day or two late. Consumers will still face late fees, but they will have to be 60 days late to be pushed into default.

Barred, too, will be retroactive changes in terms affecting cardholders who had committed no infractions at all. In urging Congress to act, Obama sharply criticized those sorts of "any-time, any-reason" rate increases that can suddenly double or triple the interest rate on a customer's existing balance. Many consumers complained that such tactics amounted to bait-and-switch.

Critics say the credit card industry's outrageous practices caused its fall from grace even as it made Visa, MasterCard, and American Express into synonyms for the good life and enabled U.S. consumers to build up nearly $1 trillion in balances on revolving credit accounts.

The credit card industry did not accept defeat quietly. To the end, it argued that its detractors did not understand the sophisticated business model it had evolved: pricing credit according to risk, and repricing it continually as consumers' circumstances changed.

One thing both sides agree is that the new law reflects a shift in the political pendulum - away from the laissez-faire lending environment that allowed practices that federal regulators and lawmakers ultimately deemed unfair and deceptive, and toward a more regulated marketplace.

In interviews last week, advocates representing consumer groups and lenders both said the bipartisan success of the legislation, which will force credit card companies to revamp their business models, was a sign of the political moment.

They said the credit crisis, economic meltdown, and bank bailouts made credit card lenders a politically juicy target and undercut the finance industry's vaunted ability to get its way in Washington.

"There was a need for Congress and the president to appear tough on banks, and an easy and politically expedient way to do that was to crack down on card issuers," said Mark J. Furletti, a credit card company attorney at Philadelphia's Ballard, Spahr, Andrews & Ingersoll L.L.P. and a former researcher at the Philadelphia Federal Reserve Bank's Payment Card Center.

To be sure, the industry has hardly lost its clout. Less than a month ago, Congress disappointed the same consumer groups that pushed for credit card reforms when it refused to allow bankruptcy judges to adjust, or "cram down," the principal owed on primary residential mortgages.

Supporters said that allowing judges to reduce mortgages to the level of a home's actual market value - as they already can do with commercial properties, vacation homes, and autos - was crucial to stemming the foreclosure crisis and the collapse of housing prices around the country. Bankers said it would reduce the availability of credit and raise its cost for everybody - the same arguments they made against the new credit card rules.

Why the difference? One reason is that the cramdown proposal was opposed by a broad group of lenders, including credit unions and community banks.

Far fewer lenders remain in the credit card business, which became increasingly consolidated in the 1980s and '90s as it turned to costly marketing and pricing models based on the now ubiquitous FICO score.

But a bigger distinction was the difference between troubled homeowners and card users.

Rightly or wrongly, opponents of the cramdown proposal portrayed those who would benefit as irresponsible people willing to walk away from their debts.

"They were able to paint them as deadbeats," said Ed Mierzwinski, consumer program director for the U.S. Public Interest Research Group.

That did not work in the fight over credit card abuses, because such a wide swath of victims was affected.

Some were responsible citizens who got into trouble with credit card debt because of a personal crisis such as a job loss or medical problem - much like the profile of consumers who get in over their heads and eventually wind up in Bankruptcy Court.

Advocates such as Mierzwinski say the connection is not coincidental. As such borrowers struggled to stay afloat, their credit card lenders may have sounded sympathetic. But the lenders' risk models showed they were more likely to default, so they were socked with rate increases even if they had managed to stay current on their cards. If treading water is tough at 12 percent, it is even tougher at 29 percent.

But it was another category of borrowers who surely became the industry's worst nightmares. People like Larry Hrebiniak.