The government this year will post a budget surplus of about $70 billion - the first surplus in a generation - President Clinton announced Wednesday. He said his administration deserved most of the credit for restoring discipline to federal taxing and spending.

On this final day of the fiscal year, Clinton said the 1998 surplus, first since 1969, signaled an important shift that opens the door to sustained growth of the American economy into the 21st century."Tonight at midnight, America puts an end to three decades of deficits and launches an era of balances and surpluses," Clinton said at a White House ceremony attended by many congressional Democrats - including some who lost their seats in 1994 after voting for Clinton's deficit-reduction plan.

"We now have to do more to see that our people can participate in it fully," Clinton said.

A key priority, he said, is to resist the temptation to spend the surplus on tax cuts until reforms are made to save the Social Security system.

Republicans were quick to share the credit and push their proposal for major tax cuts this year.

"Because of the Republican Congress, we've balanced the budget," Rep. Bill Archer, R-Texas, said in a statement issued just moments before Clinton spoke. He said voters deserve a lightening of their tax burden, "since American taxpayers are now paying more in taxes than the government needs."

The surplus announced Wednesday is an estimate; data on 1998 revenue collections and spending won't be final until mid-October. Whatever the final figure, it will be the government's first black ink since a $3 billion surplus in 1969 and will provide a political boost to incumbents of both parties eyeing the Nov. 3 congressional elections.

On the stage behind Clinton was a digital display with the word "surplus" flashing constantly.

"We ought to keep the economy growing," Clinton said, not only by maintaining budget discipline but also by maintaining a leadership role in the global economy.

He said Congress owes it to the American people not to squander the surplus.

"Nobody's being asked to cut their throat" by making the kind of politically risky votes that Democrats made in 1993 to pass the administration's deficit-reduction plan, Clinton said in stern tones.

"If we squander this surplus and start spending a little here and a little yonder on tax cuts just because we're a few weeks before an election . . . what are we going to do when times get tough?" he asked.

The last federal surplus was in 1969 and totaled $3 billion. The shortfalls peaked at $290 billion in 1992 but have fallen every year since.