Shoppers unexpectedly paused their spending in December from November, closing out the holiday shopping season and the year on a lackluster tone. The report, issued by the Commerce Department on Tuesday, surprised economists who were looking for growth despite mounting concerns about a slowing job growth, uncertainty about President Donald Trump's tariffs and other economic headwinds. And it raised questions about shoppers' ability to spend after they have remained resilient for months despite souring consumer confidence, economists said.