President-elect Barack Obama warned Thursday that the U.S. recession could “linger for years” if Congress fails to support his emerging economic stimulus plan. “I don't believe it's too late to change course, but it will be if we don't take dramatic action as soon as possible,” Obama will tell an audience at George Mason University in Virginia, according to excerpts from his prepared text that were released in advance. The speech, one of Obama's biggest events since winning the election, is part of a campaign to garner support for a potentially enormous economic stimulus package. “A bad situation could become dramatically worse,” Obama's speech warns. The speech is backed up by economic data released this week showing a rise in continuing jobless claims and a congressional research estimate that the federal budget deficit will reach $1.2 trillion this year, nearly three times last year's record figure. In his speech, Obama argues that the private sector cannot undertake all the work needed to restart the economy. “At this particular moment, only government can provide the short-term boost necessary to lift us from a recession this deep and severe,” the speech said. The details of the economic stimulus plan have not yet been finalized, but the package is expected to cost nearly $800 billion. It is likely to include tax cuts for businesses and middle-class workers, money to help states suffering from budget crises and a massive cash infusion for infrastructure building that Obama hopes will create new jobs.