this is the "cbs evening news" with scott pelley reporting tonight from washington. >> pelley: good evening. it was a striking thing, today, to hear the president of the united states say that he cannot guarantee the 27 million social security checks that you are due to be mailed august 3rd. august 3rd is the day after the government will default on its debts if democrats and republicans do not agree to increase the nation's borrowing limit. both sides say they won't raise the limit without a deal to massively cut the federal deficit. a u.s. default would shake the world economy. the stakes could not be higher. time is growing short. in our interview, president obama said the situation is dangerous. >> we met the president this morning at the white house on another day of deadlock. the question is whether a deal to cut the federal deficit will include tax increases as democrats insist, or rely only on budget cuts as republicans