FASTEN your seat belts indeed! The new round of budget cuts planned by the White House would deeply alter the federal role in the American political structure. The proposals, according to some longtime Washington-watchers, could also produce a public backlash against Republican control of the Senate in 1986 and the White House in 1988.
The budget proposals, which are admittedly still in the discussion stage, do represent a starting point in the coming fiscal and tax debate. But the guarded reception that greeted leakage of the plan in congressional quarters, including among many Republicans, should come as no surprise to the Oval Office. The ultimate outcome of the proposals seemed almost implicit in Budget Director David Stockman's opening words reportedly used in outlining the plan: ''Fasten your seat belts.''
Before the congressional budget-cutting session starts up, the engine driving the current plan - the so-called ''freeze plus'' option put forward by Mr. Stockman's shop at the Office of Management and Budget - deserves a major overhaul. Three points warrant comment:
* First, President Reagan is on solid ground in moving forward with a budget-cutting program to reduce federal deficits, projected in the range of $ 200 billion annually over the next several years. That is not in dispute.
* Second, the deficit-reduction effort must be nonpartisan. The public is in no mood for partisanship. If Democrats are asked to join Republicans in enacting a program, the Democrats should not then be put on the spot for doing so in the 1986 elections.
* Third, and perhaps most important, the budget-cutting issue should be intellectually ''neutral,'' to borrow a term that the administration is using to describe its new flat-tax plan - neutral in the sense that (on paper at least) it does not raise more revenues than are currently raised under the existing graduated income tax structure.
When examined in terms of ''neutrality,'' serious questions have to be raised about the new OMB proposals.
To its credit, the White House appears to be coming around to accepting a slowdown in defense spending, although details have yet to be announced. All the same, the new OMB plan looks in many ways more like an ideological assault on the structure of federal government than a detached effort to lower the deficit. Some of the savings make sense. But one of the primary goals of conservatives over the years has been to get the government entirely out of programs that directly aid or benefit individuals, interest groups, and corporations. Such an ideological bent does, of course, have its validity. The government has in many respects gone too far in aiding special-interest groups of one type or other. And there are few journalists who have ever covered Washington and the Pentagon who do not have their own firsthand horror stories to relate about federal waste.
But reforming such programs is quite different from entirely gutting them. To curb them entirely would make government's role narrowly passive - except for a vigorous defense program, interest on the national debt, and basic income-security programs. What is to be thought of a government that spends billions on weapons and yet nothing on public libraries? Or nothing new on helping overseas nations buy its commerce? Or little on shoring up the small business sector - the one area of the economy that tends to create jobs? All that, and more, would happen if the planned OMB budget cuts occurred. Federal assistance to libraries would end. The Small Business Administration would end. Federal subsidies would end or be sharply reduced for Amtrak. For the space research program. For mass transit. There would be deep cuts in student loans. Child nutrition. And on and on. It's no wonder that, for some critics, the planned cuts sound more like a budget for a military-oriented Sparta than for the United States of America.
Congress is not expected to approve such drastic cuts. And it should not. Perhaps the White House itself realizes that, and is merely offering up the budget as a debating point to be cited later - if Congress were to adopt much smaller cuts. Whatever, there are alternatives. Sens. Robert Dole, Ernest Hollings, and others, for example, have broached the concept of a more broadly based ''freeze'' on federal spending - including Pentagon spending - which would hold the fiscal year 1986 budget close to the outlays in fiscal year 1985. Such an across-the-board approach makes far more sense than the highly selective ''freeze plus'' administration plan.