THE SECOND-HIGHEST financial hurdle for most middle-class families, after buying a house, is educating the children. With the cost of a year at college running from $4,000 to $13,000 for a resident student, it takes more than brains to get a degree. The costs of college have preoccupied presidents and congresses ever since World War II, for there's the strongest national interest in keeping education open to everyone with the will to pursue it. Last week, as part of the annual pre-budget fanfare, the White House let it be known that President Reagan is considering several proposals--one of them new, two of them depressingly familiar--to help parents with school and college tuition.

The new idea is the Independent Education Account, a tax-free savings account like the present Individual Retirement Account. As in the case of the IRA, parents would pay taxes on the money only as they withdrew it from the account. Like any tax deduction, it would give the greatest benefit to people in the highest tax brackets. It wouldn't do much for education, but the justification would lie rather in encouraging saving. That's worth doing, but, because it mainly assists the well-to-do, it would need to be tightly limited. 2 The tuition tax credit--a glittery idea that comes shooting across the horizon periodically, like Halley's Comet--belongs in the category of things not to do under any circumstances. It would be extremely expensive to the federal government, if it was large enough to make any real difference to students and their families. If the federal government wants to expand its support for students, it would do far better to expand its present system of loans and grants based on people's ability to pay.

The White House is also murmuring about a new variation on the old tuition voucher plan. That also belongs in the category of things not to do. The thought is, apparently, to give a child a voucher representing his share of federal aid, and let his parents send him wherever they choose. There has been a tremendous amount of discussion of vouchers over the past two decades. The Reagan administration might want to ask why nothing has ever come of it. One answer is that it encourages ethnic and social segregation. Another is that to make federal tuition payments to schools run by churches would presumably be unconstitutional.