The House leadership has promised to bring to a vote before the end of the year a new proposal for holding down federal spending, a proposal some people think -- and others fear -- may work.

It would set a new standard for juding each year's budget: not just the size of the deficit it entails, but the share of national resources it commands.

It would amend the Congressional Budget Act to require that spending be held below 21 percent of the U.S. gross national product of next fiscal year and 20 percent thereafter.

In relative terms, this would force Congress to shrink the government a little, since spending is expected to be 21.9 percent of the GNP this fiscal year. Each percentage point of the GNP is currently worth about $25 billion.

The proposed percentage-of-GNP limitations could be breached by future congresses -- there is no way one Congress can bind its successors -- but only by explicit majority votes in both houses.

The leading advocate of the new form of discipline is Rep. James Jones, the increasingly influential fourth-term conservative Democrat from Oklahoma who is a member of both the Ways and Means and Budget committees.

Jones won the leadership's promise of a vote on his amendment in return for rounding up needed votes earlier in the year, first on a debt limit bill and then on the second budget resolution.

Jones and others voted then for a higher deficit and more debt than they wanted to; now they want to close out the year with an offsetting vote for restraint.

"I personally promised members who voted for the budget they would have a limit to talk about before they go home and someone starts raising hell about their budget vote," Jones said.

Measured as a percentage of the gross national product (the market value of all goods and services produced in this country), federal spending has increased perceptibly in the last 20 years. In the late 1950s and early 1960s, it generally was less than 19 percent a year; in each of the last five years, it has been more than 20 percent, and in fiscal 1976 went as high as 23.1 percent.

Most of this increase has come in waht are known as tranfer payments, the great check-writing programs such as Social Security that make up nearly half the budget each year and on which millions of people depend for income. The defense budget has actually declined in percentage of GNP. f

President Carter promised during his campaign in 1976 to stop this upward creep in government spending, much as the Jones amendment is intended to do, and said he would cut outlays back to 21 percent of GNP by the end of his first term. In the Budget he sent to Congress last January, Carter estimated that spending in, fiscal 1981, which begins next Oct. 1, would be 20.3 percent of GNP, even less than Jones' amendment stipulates.

If the budget document is to be believed, Carter and Congress already are heading where Jones' amendmemt would make them go, so the amendment would not pinch much.

One trouble with this is that Carter's budget failed to foresee the recession that is developing.

In a recession, federal spending tends to rise as a percentage of GNP for two reasons: GNP stops growing (that is the definition of recession) and the budget starts growing faster than usual as such antirecession programs as unemployment compensation and welfare automatically pick up part of the slack.

One reason spending was 23.1 percent of GNP in 1976 was that the economy was shrunken by recession -- the largest since the Depression of the 1930s -- and spending under these offsetting programs increased.

Partly because of this, House leaders are skeptical of the Jones amendment, which they fear could be too restrictive. Jones, however, argues that it would leave Congress all the latitude it needs.

Jones' proposal grew out of the balance-the-budget fever that swept across the states and into Congress earlier this year. As legislatures in state after state adopted resolutions calling for a constitutional amendment to balance the budget, members of Congress -- particularly Republicans -- began to echo the demand.

But locking a balanced budget into the Constitution would present grave problems in allowing some spending flexibility for emergencies.

Jones believes his way of limiting s pending would have teeth, without being inflexible. A majority vote to go over the limit would provide an escape clause. Republicans wanted to require a two-thirds majority vote to break the limit, but that proved unacceptable to Democrats.

The Oklahoma Democrat has picked up a powerful ally in Budget Committee Chairman Robert Giaimo (D-Conn.).

Giaimo has become convinced of the necessity of holding down spending. Yet House members continue to vote for spending items popular with the votes back home or special interests, while increasingly balking at voting for higher deficits or increasing the debt limit to pay for this spending.

"I'm very concerned about the budget process. The question is how serious Congress is about it," Giaimo said. "It's become too easy to demagogue spending on the budget. Republicans . . .voted for reconciliation [a process that would demand committees save a certain amount of money] then . . . they voted to kill hospital cost containment, which would have made up $640 million worth of that saving."