If many voters are fuzzy on the events that over the weekend forced Lehman Brothers Holdings Inc. into bankruptcy and Merrill Lynch & Company to be swallowed by the Bank of America Corporation, the continuing chaos among the most venerable names in American finance — coming on top of the recent government seizure of mortgage giants Fannie Mae and Freddie Mac and the demise of the Bear Stearns Companies — has stoked their anxiety for the economy, the foremost issue on voters’ minds.

So it was that first Mr. Obama and then Mr. McCain rushed out their statements on Monday morning before most Americans had reached their workplaces.

To the extent that travails on Wall Street and Main Street have both corporations and homeowners looking to Washington for a hand, that helps Mr. Obama and his fellow Democrats who see government as a force for good and business regulation as essential. Yet Mr. McCain has sold himself to many voters as an agent for change, despite his party’s unpopularity after years of dominating in Washington, and despite his own antiregulation stances of past years.

Mr. McCain was quick on Monday to issue a statement calling for “major reform” to “replace the outdated and ineffective patchwork quilt of regulatory oversight in Washington and bring transparency and accountability to Wall Street.” Later his campaign unveiled a television advertisement called “Crisis,” that began: “Our economy in crisis. Only proven reformers John McCain and Sarah Palin can fix it. Tougher rules on Wall Street to protect your life savings.”

Mr. McCain’s reaction suggests how the pendulum has swung to cast government regulation in a more favorable political light as the economy has suffered additional blows and how he is scrambling to adjust. While he has few footprints on economic issues in more than a quarter century in Congress, Mr. McCain has always been in his party’s mainstream on the issue.

In early 1995, after Republicans had taken control of Congress, Mr. McCain promoted a moratorium on federal regulations of all kinds. He was quoted as saying that excessive regulations were “destroying the American family, the American dream” and voters “want these regulations stopped.” The moratorium measure was unsuccessful.

“I’m always for less regulation,” he told The Wall Street Journal last March, “but I am aware of the view that there is a need for government oversight” in situations like the subprime lending crisis, the problem that has cascaded through Wall Street this year. He concluded, “but I am fundamentally a deregulator.”