For months, the American economy has been assailed by a wave of troubling news, from plunging housing prices to the soaring cost of oil, provoking gloomy talk of a possible recession. Yet so far the economy has found a way to shrug it all off and keep growing.

How much longer can the expansion carry on? As a new year unfolds, analysts expect a verdict soon: Either the negatives finally metastasize and drag the economy down, or a fresh source of growth emerges, helping to sustain consumer spending despite the ongoing worries about housing and tight credit.

The year that just ended was not for the faint of heart. As mortgage debt became synonymous with toxic waste, banks got spooked and tightfisted. Job growth slowed. Inflation fears grew. Still, consumers kept spending, and unemployment stayed flat. American companies found enough sales abroad to compensate for weakness at home.