Updated: 6:15 p.m.

As President Barack Obama signed bipartisan legislation today to rein in credit card practices that he and a majority of Congress believe are unwarranted and unfair, he also offered political aid to one of the bill’s authors.

“Mysterious fees appear on statements,— Obama said during a Rose Garden signing ceremony. “Payment deadlines shift, terms change, interest rates rise, and suddenly a credit card becomes less of a lifeline and more of an anchor.—

Obama used the occasion to buck up Senate Banking, Housing and Urban Affairs Chairman Chris Dodd (D-Conn.), who has been in political hot water over a provision he wrote earlier this year that prevented limits on certain executive bonuses. Dodd say he authored the measure at the request of the administration.

“I want to give a special shout-out to Chris Dodd, who has been a relentless fighter to get this [credit card bill] done,— Obama said to supportive applause. “Chris wouldn’t give up until he got this legislation passed. He’s spent an entire career fighting against special interests and fighting for ordinary people. And this is just the latest example.—

In an additional show of support for Dodd, Obama sent out an e-mail Friday to more than 100,000 of his supporters in Connecticut, praising the embattled Senator.

“Today — thanks to the extraordinary efforts of your senator, Chris Dodd — I signed a bill that restores a sense of fairness and transparency to the credit card industry,— Obama wrote.

The message hyperlinks to a Web page where supporters can send Dodd a note of thanks, provided they fill out their address and other information, such as whether they are a Connecticut voter.

“Will you take a moment and join me in thanking Senator Dodd for his outstanding work on behalf of families in Connecticut and across the country?— Obama wrote.

Dodd faces the most difficult re-election of his career in 2010. Former Rep. Rob Simmons (R) is the preferred nominee of party insiders, and polling has shown him in a competitive position against Dodd.

Meanwhile, Obama lauded the bill as a bipartisan effort.

“I thank the Members of Congress for putting their shoulder to the wheel in a bipartisan fashion and getting this piece of legislation done. Congratulations to all of you.—

And, amid grumbling that credit card companies will try to recoup their losses with new fees on good customers, Obama asserted that the newly outlawed practices harmed these people, too.

“I also want to emphasize these are costs that often hit responsible credit card users,— he said. “Interest can be charged even if you pay your bill on time. Rates can be increased on outstanding balances even if you aren’t late with a payment.—