The candidates are now positioning themselves for their campaigns. Mr. Mondale has a Democratic platform that is slightly more conservative than that of 1980, at least in rhetoric. And his pledge to reduce the federal budget deficit by two-thirds through taxes and spending cuts makes him sound like a fiscal conservative.
Although Mondale talks of keeping spending bills to certain limits, anyone looking at his record and his ideological thrust through the years would guess that he would press harder on getting new revenue than on cutting into social programs.
Whatever Mr. Reagan says on the subject his associates tell us that he will continue being Reagan, that he wants some domestic-spending programs reduced as a prerequisite for endorsing any big tax increase.
Reagan is apprehensive that the Democrats will push through a major plan that will keep more social programs in place and growing at a pace that will very quickly require more taxes.
Reagan will make a special point of trying to quiet the anxieties of those who benefit from such government programs. He will repeatedly assure social-security beneficiaries that they have no reason to be concerned, even though he earlier indicated that some revisions in that program might come in his second administration.
Thus, he is indicating that any changes he makes in social security would merely make it stronger financially without anyone's being the loser. But he has raised suspicions among many voters that he may be considering moving social security in the direction of gradually becoming a kind of ''safety net'' relief payment for the needy elderly - and with other citizens no longer being able to look upon the system as an important part of their retirement package.
Despite a follow-up comment from the White House reassuring social-security recipients that Mr. Reagan means them no harm, there is little doubt he will be giving social security and a whole range of other entitlement programs a hard look next year. So will Mondale.
But those who would like to see a continuation of social spending programs will believe that they have less to fear from a Democratic president. They have Mr. Reagan's often-repeated pledge to the contrary: that he came to Washington to reduce, not increase, the role of government in the affairs of individual Americans.
It was clear at the Democratic convention that it was Gov. Mario Cuomo whose theme brought the delegates together. But he did it with the old-time Democratic religion first used by Franklin Roosevelt: Cuomo was saying that the Democrats, unlike the Republicans, could take care of everyone. The Democrats, he said, would not have to drop off the poor and the disadvantaged on the long journey - the way Reagan was doing.
Then Cuomo assured everyone that the Democrats would also deal effectively with the big deficit.
And then he left the clear impression that all of this could be done without sacrifice on the part of the American public.
Now Mondale did talk sacrifice. So he was, indeed, talking sense. But, again, he left the impression, certainly with many, that these tax increases would fall mainly on the wealthy. The burden of more taxes will fall, of course, on those in the middle-income group - those sometimes referred to as the ''broad middle class.''
The fact is that these are the people who are paying most of the taxes now and who will, no matter who is president, have to pay more and more taxes.
The difference, again, on how Reagan and Mondale will approach taxation: Reagan will push much harder than Mondale for ''domestic-spending cuts.'' Also, Mondale may find some income by reducing spending for the military. But as we heard at the convention, Mondale and the Democrats are also deeply committed to a ''strong defense,'' one that will probably entail only a slight reduction in expenditures over what Reagan has been putting into his buildup.