In the next day or so, an obscure organization will meet to decide the fate of an Indian nuclear deal that threatens to rapidly accelerate New Delhi's arms race with Pakistan — a rivalry made all the more precarious by the resignation on Tuesday of the Pakistani president, Pervez Musharraf.

Nonetheless, President Bush is lobbying the Nuclear Suppliers Group, which governs international nuclear commerce, to waive its most crucial rules in order to allow the trade of reactors, fuel and technology to India. If the president gets his way, the Nuclear Nonproliferation Treaty — for 50 years, the bulwark against the spread of nuclear weapons — would be shredded and India's yearly nuclear weapons production capability would likely increase from seven bombs to 40 or 50.

India's nuclear history is checkered at best, and New Delhi has been denied access to the international nuclear market for three decades. The reasons are well known: The country has never signed the nonproliferation treaty or the Comprehensive Nuclear Test Ban Treaty, it misused civilian nuclear technology to produce its first nuclear weapon in 1974, and it continues to manufacture nuclear weapons to this day.

Paradoxically, the Nuclear Suppliers Group was formed in direct response to India's illegal 1974 nuclear test. Its central purpose is to ensure that no other country exploits foreign nuclear energy assistance to make a bomb, as India did. If the group accedes to Bush's dangerous request, countries such as Iran and North Korea would certainly use the precedent to their advantage.

The Indian nuclear deal threatens international security not only by undermining our nuclear rules, but also by expanding India's nuclear weapons program. That's because every pound of uranium that India is allowed to import for its power reactors frees up a pound of uranium for its bomb program.

Pakistan, with its unstable government and al-Qaida sanctuaries, is already ratcheting up its nuclear weapons program in an attempt to keep pace with its regional rival. Just last month, the Pakistani government darkly announced that waiving the nuclear rules for India "threatens to increase the chances of a nuclear arms race in the subcontinent."

Because changes to these international rules can be made only by unanimous agreement, every country in the 45-nation group has the ability and the duty to insist that this flawed nuclear deal be improved and to ensure that nuclear trade with India cannot benefit New Delhi's nuclear weapons program.

Thankfully, there is an easy solution. The group can say yes to nuclear trade with India if two simple conditions are met.

First, India must sign the Comprehensive Nuclear Test Ban Treaty, a step already taken by 178 other countries and every member state of the Nuclear Suppliers Group. After all, why should the group's members grant India a huge exemption from the rules that they themselves must follow?

Second, India must agree to halt production of nuclear material for weapons. That doesn't mean that India has to give up the weapons it has, or even that it cannot make more weapons with the nuclear material it has already produced.

But by closing down its manufacturing of new plutonium and highly enriched uranium, India would prove to the international community that opening up nuclear commerce would not assist, either directly or indirectly, its nuclear weapons program.

This deal was foolish when Pakistan was relatively stable; with Mr. Musharraf gone, an arms race on the subcontinent would likely be more difficult to control.

But even if the president continues to insist on the deal, he can't do it alone. He needs the 44 other countries in the Nuclear Suppliers Group to acquiesce. And the group, created to prevent the further spread of the atom, would vote itself out of existence if it allowed India to have nuclear technology with no strings attached.

U.S. Rep. Edward J. Markey, D-Mass., is co-chairman of the House Bipartisan Task Force on Nonproliferation. U.S. Rep. Ellen O. Tauscher, D-Calif., is chairwoman of the House Strategic Forces Subcommittee. They wrote this commentary for The New York Times.