THE FEDERAL budget deficit has become a menace to the financial stability of this country and most of the world. It happened over the past four years gradually, steadily and with plenty of advance warning. The signs of danger ahead are clear. Yet every past attempt to reduce that deficit has fallen into political deadlock. Who's to blame? The answer is, many people, but a handful bear prime responsibility.

First of course is the president. He was the chief advocate of the great tax cut of 1981 -- reckless legislation that Congress went along with and that has left the government far short of the revenue to pay for even the federal spending that the president himself supports. Mr. Reagan has abandoned any serious attempt to cut the budget further, but has also continued his vigorous and adamant opposition to any tax increase. How does he deal with the implications of a continuing deficit of $200 billion a year? He doesn't: he blames Congress.

But Mr. Reagan is not alone on the list. Donald T. Regan also has earned a place. As secretary of the Treasury in the administration's first term, he had a primary responsibility for the ruinous 1981 tax cut. As White House chief of staff in the second term, he has gathered the lines of power into his own hands and helped cut off the inconveniently independent views that the president used to get from the Council of Economic Advisers and the Office of Management and Budget. As long as the president is against taxes, he is unlikely to hear any doubts or suggestions to the contrary from his chief of staff.

Secretary of Defense Caspar Weinberger also bears much of the blame. His singleminded pursuit of more defense money, well beyond any justifiable claims of the defense buildup, derailed countless attempts at compromise and cooperation in reducing the deficit. The Democrats have their own sins to answer for, but it is very difficult for them to give ground on social programs when Mr. Weinberger successfully demands more for the Defense Department than it is actually able to spend. If the deficit results in the financial consequences now widely predicted, this administration in general and secretary Weinberger in particular will be remembered as having left the national security weaker than they found it -- despite those immense procurement contracts.

As for the House Democrats, Speaker Thomas P. O'Neill, Majority Leader James C. Wright and William H. Gray III, the chairman of the Budget Committee, have all made their own substantial contributions to the impasse with, most recently, their insistence on the full cost-of-living increases for Social Security benefits. Like America's military forces, so Social Security can only be damaged by the cumulative effects of uncontrolled deficits. Under the guidance of Mr. O'Neill and Mr. Gray, the Democrats' plans this season for reducing the deficit have contained too much fluff and padding to deserve to be taken wholly seriously.

A group of Republican senators has now made a sensible proposal that could reduce the deficit by half over the next three years. It's the last chance for progress this summer, and very probably the last chance in the Reagan presidency. The chief impediments to success are the attitudes and habits of those listed above. If inertia and the deficit win again, the threat to the American economy will keep rising. No one needs to be in any doubt about what's happening, or who's responsible.