“The economy, sales, employment and the stock market are all higher in spite of the bickering and rancor in Washington,” said Bernard Baumohl, the chief global economist at the Economic Outlook Group. The latest numbers “all point to an economy that is building steam and a private sector that seems almost dismissive to the sequestration and debt ceiling threats from Washington.”

Still, job growth has been modest compared with previous recoveries, and the unemployment rate has been stuck just below 8 percent since September. And Washington is gearing up for yet another showdown over fiscal policy, with severe spending cuts kicking in on March 1 if Congress fails to reach a budget bargain, just as Americans are starting to notice the larger tax bite in their paychecks from higher payroll and income taxes.

“Negotiations over the debt ceiling and the budget resolution and sequestration have the potential to be very messy and very extended,” said Ian Shepherdson, chief economist at Pantheon Macroeconomic Advisors. Businesses still seem “very vulnerable to surprises. I don’t think we’ve got the solidity and robustness and willingness to look beyond these short-term disturbances yet,” he said.

Within January’s employment report, construction was one of the more encouraging areas, adding jobs in each of the last four months. This was probably the result of rebuilding from Hurricane Sandy, unseasonably warm weather that led to fewer work stoppages and the nascent housing recovery, said Joshua Shapiro, chief United States economist at MFR.

Retailing, health care and the wholesale trade also added positions in January, while the government again shed jobs. Government payrolls shrank in most months over the last four years. The pullback in government spending, especially on the military, led to a slight contraction in fourth-quarter gross domestic product, reported on Wednesday. The decline in military spending was partly caused by uncertainty over the fiscal impasse, which eased temporarily with a compromise in Washington at the start of the year.