ANNANDALE, Va. — President Obama warned yesterday that the U.S. economy will "just sputter along" if the drive to overhaul the health care system fails this year.

At a town-hall-style meeting in suburban Washington, Obama embraced a woman who said she was unemployed, uninsured and unable to get treatment for a recurrence of kidney cancer. "You are Exhibit A" of why changes are needed, he told Debby Smith, 53, of Appalachia, Va., as she fought back tears.

The White House had solicited questions beforehand on YouTube, Facebook and Twitter. He responded to three video queries submitted to YouTube and one tweet on Twitter. The forum was live-streamed on the White House Web site.

Even so, the event at Northern Virginia Community College lacked the free-for-all quality of the town hall sessions Obama held during the campaign. The questions posed from social media networks were selected by White House staffers, and the three people he called on from the audience all were affiliated with advocacy groups that support Obama.

White House spokesman Robert Gibbs said the questions reflected "a representative sample of the issues."

The questioner on Twitter asked whether Obama would support proposals to tax health care benefits provided by employers, an idea Obama blasted during the 2008 campaign. Senate Finance Chairman Max Baucus, D-Mont., has suggested capping the amount of premiums that are tax deductible to help finance the overhaul.

"This is something that's going to be debated in the House and the Senate," Obama replied. "We're all going to have to weigh in on it." He didn't signal whether he would be willing to support curbing the tax break now.