WASHINGTON — Severe spending cuts now the law of the land, President Barack Obama and congressional Republicans refused Saturday to concede any culpability for failing to stave off what both parties acknowledged was a foolhardy way to slash $85 billion in federal spending.

The still-fragile economy braced itself for the gradual but potentially grave impact of the across-the-board cuts, which took effect Friday night at the stroke of Obama’s pen. Hours earlier, he and congressional leaders emerged from a White House meeting no closer to an agreement.

Even as they pledged a renewed effort to retroactively undo the spending cuts, both parties said the blame rests on the other for any damage the cuts might inflict.

There were no indications that either side was wavering from entrenched positions that for weeks had prevented progress on a deal to find a way out: Republicans refusing any deal with more tax revenue and Democrats snubbing any deal without it.