Washington ? Military victory in Iraq was supposed to change the psychology of nations as well as the regime in Baghdad. “For diplomacy to be effective, words must be credible, and no one can now doubt the word of America,” President Bush said in his State of the Union message in January.

It is not working that way as the occupation of Iraq stumbles toward a nominal end on June 30. The purposes and durability of the use of American military power abroad are being more loudly questioned and more persistently stigmatized in the media, on domestic political hustings and at international conclaves today than they have been since Vietnam.

This is a growing problem for Bush as he heads toward Election Day. But the consequences of failure to create a psychology of victory by following Afghanistan with Iraq are far broader than Bush’s fate at the polls. The souring of America on intervention abroad has major strategic implications for the United States and for the world.

The threshold for preventive war, for example, will be raised significantly for the immediate future. Intelligence on weapons of mass destruction and the intentions of dictators or terrorist gangs that seem to possess them are unlikely to be sufficiently clear to meet the standards for action demanded by the post-facto doubts and recriminations on Iraq. Intelligence analysis will become even more cautious and ambiguously stated to policy-makers. Vulnerability to surprise attack could grow again.

Widespread disillusionment will also seriously undercut idealistic rationales for deploying U.S. forces overseas. The growing acceptance of humanitarian intervention that gave rise to the slogan “No More Rwandas” is marginalized today by the drumbeat of “No More Iraqs.” The mishandling and abuses of the Iraq occupation have negated much of the idealism of the liberation in one long, bloody year.

British Prime Minister Tony Blair, speaking of Kosovo in 1999, called for “a new internationalism,” in which countries fight “not for territorial imperatives but for values … for a world where those responsible for crimes will have nowhere to hide.” The sentiments were echoed by Kofi Annan at the United Nations, and drew many to the cause of regime change in Iraq.

Blair’s words are quoted in “The Breaking of Nations,” an outstanding new short book of essays by Robert Cooper, who once served as an adviser to Blair and is now a senior official at the European Union in Brussels. Cooper treats Blair’s high-mindedness with respectful but cool skepticism:

“Humanitarian interventions are particularly dangerous for those who intervene. It is difficult to set clear objectives; it is difficult to know where to stop,” he writes, adding that those who become involved in places such as Iraq or Sudan “run the risk that ultimately they will be there because they are there.”

The United States has “typically” stationed troops abroad “to defend its allies,” not to seek territory or empire — or to create new world orders, Cooper notes. The traditional Cold War defensive role is at an end, as decisions this month on troop redeployments from Germany and South Korea signify. But a consensus on what American troops can hope to accomplish in the Middle East or elsewhere is ever more elusive as the problems of intervention rather than its uses dominate U.S. national attention.

Unfortunately, Bush has compounded the confusion by prolonging Iraq’s occupation and its aftermath, and blessing naked expediency in Baghdad, where the new prime minister is a long-time CIA asset who is accused in The New Yorker this week of having once been part of Saddam Hussein’s execution squads.

Americans have lost sight of the mass graves of Iraqi Shiites, the genocide campaigns against the Kurds and the war crimes committed by the criminal Baathist regime that was overthrown a year ago. The benefits of fighting terrorist networks in the Middle East and thereby galvanizing the Saudi, Moroccan and other Arab regimes to take forceful action against their extremists are not described or seen clearly enough to counterbalance the abuses of Abu Ghraib or the problems of Fallujah.

Instead, Washington is in the grips of an overlapping series of blame games geared toward influencing the November elections, ruining the reputations of rivals and obtaining or protecting jobs for the professionally ambitious and the ambitiously professional. Perspective on the future of America’s role in Iraq, the Middle East and the world is quickly jettisoned in this psychological sourness. So are the once bright hopes of humanitarian intervention.

Jim Hoagland is a columnist for Washington Post Writers Group.