Washington ? President Bush is rushing the clock and running out of time as he tries to stare down nuclear threats on three fronts.

Bush has seen Iran ignore a weekend deadline to say whether it will haggle with the U.S. and others worried that Iran is racing toward the bomb. And he has just days to decide whether to reward another adversary, North Korea, for inconclusive steps to get rid of weapons it already has.

Iran’s non-answer highlights that Bush has run out of time to see through either deal and another with nuclear-armed India. That means the next U.S. president will have to pick up the pieces, and possibly change the terms of any deals.

Bush, traveling today to South Korea, will be on the spot to explain his next move with the inscrutable North. Pyongyang expects Bush to remove it from the U.S. list of terror-sponsoring countries as soon as next weekend, as promised when the North blew up its nuclear cooling tower in June. Bush will insist that the North first agree to international terms for checking up on its disarmament work.

Whenever it comes, the reward is almost sure to be the last act for the Bush administration in stop-and-start bartering with the Stalinist regime that has given Bush political heartburn on the right.

That second-term gambit, like the offer to Iran, would buy off nations Bush once called part of an “axis of evil” in the interest of reducing or containing the spread of nuclear weapons.

He will leave office without any clear payoff, beyond the good will of other nations pleased at the softening of tone and tactics.

Bush’s administration also offered India novel cooperation in developing civilian nuclear energy that critics say would let India build up its nuclear arsenal and spoil global efforts to stop the spread of atomic weapons. The deal survived what had seemed fatal opposition in India only to fall victim to the election-shortened U.S. legislative calendar.

All three situations show what the administration calls flexibility and its critics call tunnel vision, and it is an open question whether, if ever closed, the deals would really lower the risk of nuclear war.

“Although it may be possible for a new U.S. administration to repudiate the disastrous Bush policy,” of case-by-case dealmaking, “a tremendous amount of damage will already have been done,” said William C. Potter, nonproliferation director at the Monterey Institute of International Studies. He said the India deal is the worst of the three.

The Iran and North Korea negotiations involve offers made by the United States together with other nations, and a new president is not likely to pull out of those coalitions right away.

Republican John McCain is somewhat skeptical of the Iran offer but says he would pursue both diplomacy and punitive sanctions. Democrat Barack Obama would expand talks with Iran on merits.

Iran, though it has no nuclear weapons and claims it isn’t seeking them, has received the most attention.

Six major world powers agreed Monday to seek new sanctions after the country failed to respond to an offer intended to defuse the dispute over where its fast-track nuclear development is headed.

Tehran has said it will deliver a written response to the offer on Tuesday, three days late by U.S. count. U.S. diplomats say they don’t expect a clear answer; many analysts assume Iran is running out the clock on Bush in hopes of getting a better deal from the next president.

The sanctions machinery was too slow for Bush’s taste even when he held more leverage than he does in his waning months. Security Council veto-holders Russia and China have opposed harsh measures and have little incentive to take a firmer line, or move any faster, at this point.