Congress will soon take a hard look at President Bush's plan to share civilian nuclear technology with India, a proposal that could bolster an important U.S. ally — though some fear it would open the floodgates to nuclear proliferation.

Bush and Indian Prime Minister Manmohan Singh (search) announced the agreement during a visit to Washington last month. Before the technology can be shipped to India, Congress must approve an exception to — or change — the U.S. law banning civilian nuclear cooperation with countries that haven't submitted to full nuclear inspections.

The administration will start pushing its case in earnest after lawmakers return from their summer break Sept. 6. Already, Secretary of State Condoleezza Rice has sought support from congressional leaders.

Some legislators believe the deal would rewrite the rules on how the world exchanges nuclear supplies. India has refused to sign the international Nuclear Non-Proliferation Treaty (search), and some fear that the Bush plan could eventually allow rogue countries outside the NPT to build nuclear weapons programs with imported civilian nuclear technology.

Others call it a clever U.S. strategy to help sate a thirst for energy in the world's largest democracy while setting up nuclear safeguards. If China's influence in Asia is counterbalanced by India's new strength and prestige, they argue, so much the better.

The stakes of the debate are high, and other nuclear powers — and those who hope one day to join the club — will closely watch what Congress decides.

"At the end of the day, historians are going to judge this agreement primarily by whether or not it does provide a convenient pretext for other non-nuclear weapons states to become nuclear weapons states," said Robert Hathaway, director of the Woodrow Wilson Center's Asia Program.

Indian and White House officials are working on the deal's specifics, and both sides have agreed to review their progress when Bush visits India in the spring.

While many lawmakers are undecided or aren't making public their views yet, Sen. John Cornyn said he supports it.

"It just makes enormous sense that the world's largest democracy and the world's oldest democracy get together and work together in pursuit of our common values," said the Texas Republican. Cornyn chairs the bipartisan India Caucus, which promotes Indian affairs in Congress.

For some, however, the deal would ruin the Nonproliferation Treaty, which was created, in part, to allow civilian nuclear cooperation with those countries that agree not to pursue nuclear weapons. Critics question how the Bush administration can provide nuclear technology to India, which besides shunning the NPT conducted nuclear tests in 1974 and 1998.

"With one decision, Bush has made a mockery of the Nuclear Nonproliferation Treaty and the likelihood that any other country in the world will take it seriously," said Democratic Rep. Edward Markey.

In return for U.S. civilian nuclear technology, India says it will separate its civilian and military nuclear facilities, declare its civilian facilities to the United Nations' nuclear watchdog agency and continue a self-imposed moratorium on nuclear testing.

Undersecretary of State Nicholas Burns has said that India's promises "will, in effect, in a de facto sense, have India agreeing to the same measures that most of the NPT states have agreed to."

Dennis Kux, a retired State Department South Asia specialist, said the deal "would create a new category of states, with India the first member. It sets a precedent: we're saying you can be a responsible nuclear player, by following the NPT norms, without being in the NPT."

As he works to persuade Congress, Bush will likely have the support of a large group of legislators from both parties eager to encourage India's recent economic success. In the 100-member Senate, the India Caucus chaired by Cornyn and Sen. Hillary Rodham Clinton, a Democrat, includes more than 40 lawmakers.

Democratic Rep. Frank Pallone, the founder of the House India Caucus, which has nearly 200 members, said India would use U.S. nuclear technology responsibly "because everything in India is civilian controlled. They have no history of trying to send nuclear weapons or technology to third parties."

Still, some worry how the world's other nuclear powers will view a unilateral decision by the United States to loosen restrictions on the distribution of nuclear supplies.

"The signal is that we want to change the rules of the game," said Michael Krepon, an expert on South Asia at the Henry L. Stimson Center. "Other nuclear suppliers will be very free to reinterpret the rules as they like in subsequent cases."

India's nuclear rival Pakistan, where scientist A.Q. Khan (search) ran a network smuggling nuclear technology to Libya, Iran and North Korea, will be particularly interested in what happens in Congress.

"This is a big deal for Pakistan," Krepon said. "If an exception is to be made for India, it should be made for Pakistan, as well. That's Pakistan's position."