For a country eager to see trade sanctions eased, Iran is taking an unseemly amount of time in meeting a key requirement of that shift - full cooperation with International Atomic Energy Agency officials in their effort to assure that the nation is no longer pursuing nuclear weaponry.

The theocratic Iranian government has been aware of this condition for years, and has been in negotiations over it for a year, first in secret talks with the United States and for the last three months with representatives of the permanent members of the United Nations Security Council plus Germany.

On Sunday, it finally agreed to open some of its books and installations to international inspection - but not until the middle of May. The extended delay intensifies justified suspicions about Iran's intentions.

Maybe Iran's leaders don't mind creating more uncertainty about their nuclear program. After all, sanctions have already been partially eased in exchange for actions that Iran claims can be reversed overnight, including getting rid of its stockpile of enriched uranium that puts it closer to nuclear-arms-grade material.

And according to Hossein Sheikholeslami, an Iranian official in charge of meeting with international business interests, the remaining sanctions are already crumbling. He defiantly told The New York Times: "The sanctions regime imposed on us is falling apart."

Israeli Prime Minister Benjamin Netanyahu recently made the same point: "As we have warned, and I say this with regret, the sanctions regime has started to weaken and very quickly. If tangible steps are not taken soon, it is liable to collapse, and the efforts of years will vanish without anything in exchange."

U.S. officials continue to say that sanctions will remain in force until Iran satisfies international demands that its nuclear program is verifiably peaceful. Yet President Barack Obama rejects bipartisan congressional efforts to have standby sanctions ready if Iran doesn't follow through on its promises to defuse nuclear concerns.

President Obama says such a law would cause the talks to fail.

But if the sanctions are already weakening, Iran has little incentive to bring the talks to the conclusion the president seeks. Without the proposed standby sanctions, he is not negotiating with a strong hand.

And without a more realistic response to Tehran's familiar stall tactics, the international community will keep playing a sucker's game with the Iranian regime.