India's foreign secretary is visiting Washington this week, the start of a monthlong effort to help President Bush sell his landmark civilian nuclear cooperation deal to a skeptical Congress.

Following Foreign Secretary Shyam Saran's trip, scheduled to begin Tuesday, a string of Indian ministers will meet in coming weeks with U.S. lawmakers and speak at think tanks, press conferences and business gatherings across Washington. They will argue that a U.S.-Indian deal to share nuclear technology and fuel is crucial for a close U.S. ally determined to meet massive energy demands.

Hard questions, however, are expected from lawmakers, some of whom worry the deal could ruin international efforts to stop the spread of nuclear weapons technology.

Jon Wolfsthal, a nonproliferation analyst with the Center for Strategic and International Studies, said Congress was largely shut out of earlier negotiations on the deal. Meetings with Indian ministers, he said, will give lawmakers a chance to push India on issues the Bush administration has said India considers as deal-breakers, such as trying to get India to sign a moratorium on the production of nuclear materials.

Lawmakers, he said, "are going to want to find out for themselves where the limits of Indian flexibility are."

Christine Fair, a South Asia analyst with the congressionally funded U.S. Institute of Peace, said the Indian ministers "know they have an uphill battle."

"There are a lot of skeptics in Congress who do not believe that we need to have a nuclear deal inked with the Indians for our relationship with the Indians to go forward," she said.

Since Bush and Indian Prime Minister Manmohan Singh agreed to pursue an accord on nuclear cooperation earlier this month in India, administration officials have waged an aggressive campaign to convince lawmakers and the public that the deal is the cornerstone of a new global partnership with India.

They say the pact brings India into the nonproliferation mainstream by increasing international inspections and putting U.N. safeguards on India's civilian nuclear power industry. The deal also reduces India's dependence on fossil fuels, supporters say, by allowing it to build more nuclear power plants.

Critics say U.S. and Indian efforts are an attempt to sell a flawed deal to lawmakers increasingly willing to question Bush's leadership as the president's popularity plummets and elections approach.

Henry Sokolski, executive director of the Nonproliferation Policy Education Center and a former Pentagon official, said the Indians' visit reflects a State Department that does not "think they can sell this thing alone. They need all the help they can get."

Congress is considering a bill that would exempt India from U.S. laws that restrict trade with countries that have not submitted to full nuclear inspections. New Delhi has refused to sign the international Nuclear Non-Proliferation Treaty and conform to its inspection regime.

The United States and India agreed in early March that India would separate its civilian and military nuclear facilities. The two countries still must negotiate the conditions, duration and scope of the overall cooperation plan.

Rep. Ed Markey, D-Mass., said in a statement Monday that the Bush administration "is looking to snooker Congress into signing an agreement now, promising that details will follow later."

The Bush legislation, he said, reduces "Congress to the role of a passive rubber-stamp with respect to one of the most critical nuclear nonproliferation issues of the last decade."