And U.S.-Russian relations could come under greater strain if Washington pushes ahead to challenge its other "axis of evil" foes, Iran and North Korea, with whom Russia shares longstanding political and economic ties.

If the U.S. attempts to deal with either Iran or North Korea in a way that angers the Kremlin, then "Russia will hardly exercise restraint, including in its supplies of technologies," says Sergei Rogov, head of the USA-Canada Institute in Moscow. "If America decides to repeat the Iraqi precedent, the fragile Russian-American partnership will fall apart for good."

Before the war in Iraq, the Kremlin and Washington alike touted the "special relationship" between Presidents Bush and Putin that could pave over post-Cold War tensions, and the two heads of state appeared to hit it off on Mr. Bush's Texas ranch.

Although they disagreed over the expansion of the North Atlantic Treaty Organization and the U.S. abandonment of the antiballistic-missile treaty, the two leaders agreed there was an overarching need for the nuclear powers to cooperate. The Russian president was the first world leader to offer his condolences to the White House after the Sept. 11 terrorist attacks, and supported the U.S.-led invasion of Afghanistan.

But this civility is starting to crack under the weight of old suspicions. Last week, as Washington protested alleged Russian arms sales to Baghdad, the rhetorical disharmony hit a peak. Moscow called the accusations unfounded "war propaganda" and protested spy-plane flights near Russia's southern border.

The U.S. has been further irked by Mr. Putin's strong and public opposition to war. Last week, he called the conflict the most serious crisis since the end of the Cold War, warning that it threatened "the foundations of global stability and international law."

Analysts see the public sparring as a sign that the U.S.-Russian friendship is shallower than advertised.

"When countries say they have a partnership, it implies they can manage problems on the middle or high levels of government -- the head of the National Security Council calls his counterpart in Moscow and they discuss things," says Andrei Safranchuk, head of the Center for Defense Information in Moscow. "This past week we saw that this wonderful partnership does not work."

Washington and Moscow say they are trying to contain the dispute, but if it continues to seethe, the rhetoric could complicate cooperation on issues that both sides care about, such as arms control and terrorism.

Part of the problem, analysts say, is that the rank-and-file bureaucrats in Washington and Moscow haven't changed markedly since the days of the Cold War. Much of the Bush team dates back to the Reagan era, when Russia itself was called the center of an evil empire. Most of Mr. Putin's top advisers in the Foreign Ministry and the military are also holdovers from Soviet days, and are suspicious of U.S. intentions.

Washington's accusations last week that Moscow had sold sensitive military equipment to Iraq were a clear sign of the breakdown in communication. The U.S. said it had tried since last summer to halt Russia's sales of antitank guided missiles, global-positioning-system jamming devices and night-vision goggles to Iraq, fearing they could pose a danger to U.S. troops. But warnings were ignored in Moscow, U.S. diplomats said.

"They do not want this to be an irritant in our relationship. And they are hard at work on it. And I hope they will find out what we know to be the case, and deal with it," Secretary of State Colin Powell told a congressional committee last week.

The White House was fairly confident it could win Moscow's tacit acceptance of war by promising that Russia's economic interests would be honored in a post-Saddam Hussein Iraq. But economics didn't bother Mr. Putin nearly as much as the precedent of the U.S. unilaterally overthrowing a regime.

There is tension on other fronts, too, including Iran and North Korea. Washington has protested Russia's sale of civil nuclear technologies to Tehran, saying the materials and know-how could be used to build bombs.

Both presidents now face a choice: abandoning partnership in a huff or redoubling efforts to find common ground. Doing the latter in the current political climate will be tough. The American public is casting a suspicious eye on what it sees as fair-weather allies who oppose the war. Russians, meanwhile, have grown increasingly wary of American might. In an opinion poll of 1,600 Russians last week, 55% said they view the U.S. negatively, compared with 15% polled last summer.

Even during the Cold War, when Moscow and Washington hated each other, "ordinary people really liked Americans," says Alexei Arbatov, a liberal legislator and deputy chairman of the defense committee in the lower house of Parliament. "Now, the sincere feeling on the street ... is taking on a bright anti-American character."

HISTORY OF A SPECIAL RELATIONSHIP

• June 2001: Putin and Bush meet for the first time; Bush declares Putin trustworthy.
• September 2001: Putin is the first world leader to call Bush after Sept. 11 terrorist attacks to offer his condolences and pledge support in the fight against terror.
• November 2001: Bush entertains Putin at his Texas ranch, where they agree to reduce nuclear arsenals.
• February 2002: Putin calls U.S.-Russian cooperation important for world stability, but he warns Washington against attacking Iraq unilaterally.
• May 2002: The two leaders sign a nuclear-arms reduction pact and pledge to cooperate on energy issues. But Bush team criticizes Russian nuclear aid to Iran.
• November 2002: Russia supports U.N. resolution on sending weapons inspectors to Iraq. But Putin warns Bush not to lose focus on the war against al Qaeda terrorists.
• February 2003: Putin declares that Russia stands with France and Germany in favor of continued weapons inspections in Iraq and against any U.N. resolution authorizing force against Saddam Hussein.

See also:

Situation Around Iraq

Russia - US Relations

Wall Street Journal, April 1, 2003