While the national debt continues to soar to unimaginable heights, the latest word from Washington is that it won't be until late summer before Republicans and Democrats stop the political jostling and start tackling the budget deficit in earnest.

The Republicans, with President-elect George Bush in the vanguard, are adamant that any tax increase to lower the national debt deficit will backfire and only lead to increased spending. Democrats, meanwhile, are digging in their heels to oppose any deficit-reduction plans unless they include a tax increase.Influential Democrats on the National Economic Commission - currently a 12-member bipartisan panel appointed by Congress and President Reagan to recommend ways to reduce the budget deficit - have begun discussing a proposal that would earmark any additional revenues from a tax increase for deficit reduction.

While that is an excellent idea that ought to be followed up, it does not answer the deficit problem by itself.

Former budget director James C. Miller III said because all the money goes into the same pot, it's difficult to guarantee that new revenues will be applied only to the deficit.

Yet even if such revenues are strictly applied to the deficit, a tax hike would be meaningless in reducing the flow of red ink if Congress felt - as a result of the earmarked money - that it no longer needed to cut spending in other ways.

If additional revenue is raised through a tax increase, the deficit reduction targets must be lowered by the same amount, assuring there would be no change in the spending cuts needed to reach the Gramm-Rudman targets.

Otherwise, any cuts in the deficit made by higher taxes would simply be swallowed up by increased spending in other areas - and the total deficit would not shrink at all. But earmarking any tax increase certainly would be a promising beginning.

Congress and the new president must face up to the hard and painful reality that the deficit is too big to eliminate without higher taxes and budget cuts at the same time. One without the other, simply will not work.