America got its bad report card on education just when, like a 10 o'clock scholar, it could say: ''But, Dad, I'm already buckling down and doing better.'' Recent improvements in many schools are no cause for complacency. They should not blunt a vigorous response to a blue-ribbon commission's stark warning that a ''rising tide of mediocrity'' threatens the educational system and ''our very future as a nation.''
But an up-to-date perspective is needed on the report of the National Commission on Excellence in Education. For instance, its call for higher college entrance requirements - and thus higher secondary school standards - has been anticipated in various places. Chicago schools have bolstered academic programs. California colleges have raised entrance standards. Course credit for non-academic subjects is on the decline.
In such respects the commission speaks to the converted.
Yet, as meetings on its findings are held around the country, the public will no doubt react like a parent who knows that grades on a report card are not the whole story.
What should be done for the 48 percent of American young people who are not college bound, for example? Vocational education should be saved from mediocrity no less than the traditional college-prep education that in effect would be revived (with computer literacy added) by the commission.
How should such commission goals as increased school hours and fairly compensated teachers be financed when the trend in many places is toward investing less rather than more in education? It was a conspicuous omission for the commission not to be asked for financing suggestions along with prescriptions that would cost billions of extra dollars.
The report does note that the federal government has the primary responsibility for identifying national interests in education and should help fund and support programs to support these interests. Federal funding for such specific programs as those for the handicapped is favored. But the main chore of financing and implementing the overall reforms is left to states and localities.
Ideally, the responsibilities for raising and spending money for education should be closely linked - and tethered to the communities where it is used. But a ''national interest'' in education - amply spelled out by the commission in relation to other countries and to the needs of democracy - would imply reducing the large disparities in resources and commitment to education from locality to locality. Perhaps means of doing so can be elicited in the forthcoming regional meetings.
President Reagan immediately interpreted the report as being opposed to federal intrusion in education and thus in line with his efforts to redefine the federal role. Education Secretary Bell, however, denied the report was a political document, citing the bipartisan composition and professional membership of the commission.
Mr. Reagan can help to keep the report from becoming a political plaything by not blending it in the public mind with his own political agenda. He risked doing so when he took the occasion of receiving the report to reaffirm his campaign for such highly politicized aims as tuition tax credits for education in parochial and other private schools. These credits would amount to federal funding not of public schools but of private schools.
If the United States is to resist any tide of mediocrity, its first bulwark must be its system of public education. This may have been temporarily diluted as it has grown to serve more individuals than the schools in any previous society. It can again become the glorious enterprise of which America is capable.