WASHINGTON--President Obama issued a warning Tuesday: if Congress does not raise the debt ceiling and the U.S. goes into default on Aug. 2, government checks may not go out on Aug. 3 That's what Obama said in an interview with new CBS news host Scott Pelley. The complete interview will be broadcast tonight on the CBS EVENING NEWS WITH SCOTT PELLEY (6:30 PM, ET)

SCOTT PELLEY: "Can you tell the folks at home that the Social Security checks are going to go out on August the 3rd. There are about $20 billion worth of Social Security checks that have to go out the day after the government is supposedly going to go into default."

PRESIDENT OBAMA: "Well this is not just a matter of Social Security checks. These are veterans' checks; these are folks on disability and their checks. There are about 70 million checks that go out."

PELLEY: "Can you guarantee as President those checks will go out on August the 3rd?"

OBAMA: "I cannot guarantee that those checks go out on August 3rd, if we haven't resolved this issue. Because there may simply not be the money in the coffers to do it."