But beyond this week, Wall Street has reason to be nervous as the issue plays out, said people in both parties and in finance.

Investors have grown accustomed to partisan games of chicken that always end with the needed increase in the government’s borrowing authority. But this showdown, many say, is riskier because of the strongly held antispending, antitax views of the many freshman House Republicans combined with the fragility of the economic recovery.

“The people who are more politically savvy realize this may not be the normal brinkmanship,” said Senator Mark Warner, Democrat of Virginia. Nor, he added, is this standoff like the fight a few months ago over the current year’s spending, which ended with a late-night deal shortly before the government would have shut down.

“The thing that people are missing is that in shutting down the government you can go to the 11th-and-a-half hour, and the consequences of not doing it, while significant, are not economy-threatening,” Mr. Warner said. “You can’t go to the 11th-and-a-half hour on the debt limit. You don’t know what’s going to spook the bond markets.”

The chief wild card is the House Republican majority, which was elected last November after a campaign defined by voters’ antipathy toward budget deficits. More numerous than the insurgents elected in the conservative waves of 1980 and 1994, many freshman Republicans have no experience in public office and consider themselves citizen-legislators who entered government to shrink it, regardless of the political costs.

“The people who have been sent to Washington most recently are bringing a strong message from the Republicans more to the right that really want something done about government spending,” said Joseph E. Kasputys, founder of IHS Global Insight and an official in the Nixon and Ford administrations.