The Democrats would stop writing checks for a year. President Reagan and his allies would throw away the checkbook entirely.

Vastly oversimplified, this is one of the critical differences between the two main budget alternatives now before the House of Representatives: the Gramm-Latta version of Reagan's budget, and the counterproposal drafted by the Democratic majority on the House Budget Committee.

These two versions of the first budget resolution for 1982 are similar in purpose in that both set spending goals for the fiscal year beginning Oct. 1 that are sharply reduced from current levels of spending.

They differ in that the Democrats would cut social programs by about $7 billion less than Reagan would; they would also cut taxes less.

Perhaps more important, however, they also differ in how they would cut spending and enforce the cuts under a budget control process known as "reconciliation."

The Gramm-Latta budget, drafted by Reps. Phil Gramm (D-Tex.) and Delbert L. Latta (R-Ohio), would require committees to vote cuts in the basis authorizing legislation underlying spending programs sufficiently to save $36.6 billion during fiscal 1982.

It follows the precedent of the Senate, which last month approved "reconciliation" instructions to its committees to force $36.9 billion in such program cuts.

The Democrats' budget avoids cuts in programs as such. Instead, it cuts spending on a year-to-year basis.

For entitlement programs that do not depend on annual appropriations for their funding, such as food stamps and cost-of-living increases for federal workers' pensions, it requires authorizing committees to cut $15.8 billion in spending for 1982.

For programs that are funded by appropriations, it reduces spending targets by $23.6 billion, meaning that the appropriations committees of the two houses would have to reduce spending by that amount while leaving program authorizations intact.

To assure that the cuts are made, the Democrats require that any money bills that exceed specific ceilings for each category of spending be held at the speaker's desk, pigeon-holded, until they are reduced or until the overall spending ceiling is raised.

The appropriate could be reduced by an amendment proposed by the Budget Committee. Or the ceiling could be raised in the second budget resolution, which Congress is required to pass later in the water to set binding spending limits.

In other words, Gramm and Latta would cut actual programs by means of permanent authorization charges that would stay on the books unless or until Congress changes its mind and restores the program to its previous level of authorization.

The Democrats would simply reduce spending year by year, retaining the option of raising or lowering spending levels depending on need and public opinion.