Counsel to AT&T Inc. (T - Get Report) and Time Warner Inc. (TWX - Get Report) took aim at the economic projections underpinning the Department of Justice lawsuit to block their merger, in closing arguments on Monday afternoon. 

Dan Petrocelli of O'Melveny & Myers LLP said the DOJ's case is a "house of cards" that relies on the economic model by University of California Berkeley economist Carl Shapiro, an expert witness for the government. The model contains too many flaws for him to address in a 90 minute closing statement, the lawyer said. "I'd be here for hours," he said.

The government argues that DirecTV parent AT&T will have the "incentive and ability" to drive prices higher for rival pay-television companies if it buys Time Warner. By threatening a blackout, Justice argues, Time Warner's Turner networks can jack up prices for networks such as CNN, TNT and TBS. Earlier Monday the government urged Judge Richard Leon to reject the merger, or at least to require the sale of either DirecTV or the Turner networks.