Deficit: more than a down payment needed

Considered as a ''down payment,'' a $62 billion reduction in budget deficits that will total some $550 billion to $600 billion over the next three years is not all that much.

But, since many critics said Congress and the White House would never jointly agree on such a down payment to begin with, the new three-year deficit-reduction agreement signed into law by President Reagan this week must be considered an important first step in bringing future federal deficits under control.

The $62 billion package includes $48 billion in tax increases and $14 billion more in spending cuts. It is also part of a larger $143 billion deficit-reduction agreement that lawmakers have been working on. The rest of the package - adding up to about $81 billion - is still tied up in Congress, since it includes controversial cuts in defense spending.

It is imperative that Congress and the White House agree on the remaining reductions as soon as possible. Not to do so would be to send an unfortunate signal to Wall Street - which invests in the plants and businesses that keep Americans employed - that Washington is not prepared to take action to offset the deficits and thus help hold down interest rates. Indeed, the sluggish stock market of recent weeks has clearly underscored concern in the financial community that interest rates could continue to rise, which in turn could work against recovery.

It is interesting that Mr. Reagan signed the tax-hike, spending-cut measure with little fanfare. Key Democratic lawmakers, who had joined their Republican counterparts in clearing the measure through Congress, were, of course, away at San Francisco.

The point is that reducing the deficit, for all the campaign talk that will be heard about deficits in coming weeks, remains a joint responsibility of Congress and the White House - and of both Republicans and Democrats. That means wrapping up the current $143 billion package, then starting work on a broader, more comprehensive, agreement that could be approved early in 1985, no matter who is elected president.