It was an impressive sight to see the American and Russian presidents, standing together in a gilded Kremlin hall, pledging a joint campaign against world terrorism and acclaiming the “Treaty of Moscow” they were signing as a major new step in arms control and the prevention of the spread of nuclear arms.

But if you read the text of the 475-word document and consider the disagreements expressed at the same meeting, you will see that treaty and the partnership are somewhat less than billed.

President Bush hadn’t wanted a treaty at all, proposing instead an informal agreement between the two presidents. But President Putin insisted on a formal treaty to bind future heads of state. Actually, either party can back out by giving three months’ notice.

The treaty commits each country to do what they both already had planned to do unilaterally: reduce by almost two-thirds their nuclear arsenals of about 6,000 warheads each. The maximum that each country can have by the end of the 10-year treaty term is 2,200, far more than enough to destroy all the major cities of any enemy country.

Critics contend that the treaty misses a major threat by addressing warheads rather than nuclear material that may not be adequately controlled. Former Defense Secretary William J. Perry, former Sen. Sam Nunn, and the former commander of the American strategic nuclear forces, Gen. Eugene Hasbinger, charged recently that the administration had failed to insist on an accurate accounting of existing weapons.

President Putin himself raised a question as to whether it was wise to warehouse the discontinued weapons; rather than to destroy them. He said, “There are countries that want to acquire weapons of mass destruction.” Mr. Bush argued that disarmed warheads had to be kept for spare parts and “quality control.” Mr. Putin responded that, “It’s more worthwhile, perhaps, to eliminate a certain part of nuclear potentials.”

Before Mr. Bush reached Moscow, administration officials told reporters that it was important to persuade Russia to reconsider its support of a nuclear reactor project in Iran. Mr. Bush said at the news conference that Mr. Putin “gave me some assurance that I think will be very comforting for you to listen to.”

But Mr. Putin’s response was anything but assuring. Instead, he defended Russia’s assistance to Iran as “exclusively” for purposes of developing energy, not weapons. He went on: “I’d like to point out also that the U.S. has taken a commitment upon themselves to build a similar nuclear power plant in North Korea. In addition to Iran, I think, we also need to think about other countries here. For example, we have some questions concerning development of missile programs in Taiwan and in some other countries where we’ve been witnessing active work on producing weapons of mass destruction.” He did not specify which other countries, but said he had information and stood “ready to share it with our American partners.”

The United States heads a three-nation consortium in the North Korean project under a 1994 agreement requiring North Korea to abandon its own nuclear program. Mr. Bush has lumped Iraq, North Korea and Iran together as an “axis of evil” even though the United States has been negotiating with North Korea and Iran teeters on a delicate balance between Islamic radicalism and political reform that could lead to workable relations with the West.

So, although Mr. Bush hailed “an entirely new relationship” with Russia, much remains to be done to strengthen the partnership and harness nuclear weapons.