Resident Scholar  Michael Rubin

As Iraqis marked five years since Baghdad's fall on April 9, Democrats--including Hillary Clinton and Barack Obama--grilled Gen. David Petraeus and Ambassador Ryan Crocker. Before the testimony, House Speaker Nancy Pelosi warned Gen. Petraeus and Mr. Crocker to avoid undue optimism: "We have to know the real ground truths of what is happening there [in Iraq], not put a shine on events."

Among Democrats, it is conventional wisdom that the Bush administration rushed to war, botched planning and ignored dissent. "Whether out of hubris or incompetence," Senate Majority Leader Harry Reid explained, "the president and his men willfully ignored the experts and sent our troops to battle unprepared for the consequences."

Ms. Pelosi and Mr. Reid have a point. When it comes to national security, it behooves us all to plan for the worst even as we hope for the best. But now it appears that it is Democrats who are making the mistake of being too optimistic. On Iran, North Korea, China, Russia and Venezuela, they dismiss realism and embrace the most optimistic assessments of our adversaries.

In regards to Iran, they exculpate Tehran for shipping shaped charges to Iraq, sending weapons to the Taliban, and harassing U.S. ships in international waters. Mr. Obama--embodying his party's naďve optimism--assumes Iran's good faith on just about everything. Last week, he called for a "diplomatic surge" against Iran on the same day that Iranian President Mahmoud Ahmadinejad boasted that Iran's nuclear advance marked "the beginning of the collapse of the great powers."

In regards to North Korea, 15 years of good-faith diplomacy has destabilized East Asia. And now South Korea and Japan live under a nuclear shadow. The problem is not a lack of diplomacy, but refusing to consider objective assessments. In January, U.S. Special Envoy for Human rights in North Korea Jay Lefkowitz questioned Pyongyang's adherence to nuclear agreements it has made with Washington. In response, Secretary of State Condoleezza Rice had his remarks erased from the State Department's Web site.

Not that policymakers should rush to embrace military action. Attacking Iran isn't a viable option because it would likely only delay, not eliminate, Tehran's nuclear program. Risking the blowback from an attack would only be productive if there was a strategy to use the interim period to end the threat posed by the regime's ideology. Until there is a regime-change strategy, a military strike would merely allow politicians to put off conducting a serious national security debate. An attack on North Korea would likely achieve little even while risking the loss of Seoul in a counterattack.

But if military action is risky, the idea that planners should build policy on the assumption of an adversary's sincerity is more dangerous. Even if the recent National Intelligence Estimate on Iran is correct and that country halted its nuclear program in recent years, it's still clear that so-called "reformist" governments in Iran invested billions of dollars in a covert military nuclear program. And they did so at the very time when Europeans and the U.S. officials were engaging the country in diplomacy and easing trade barriers.

Failing to prepare for the worst leads Western officials to sequence diplomacy and military planning, rather than conduct both simultaneously, which adversaries exploit. As national security adviser in the run-up to the Iraq war, Ms. Rice blocked postoccupation planning from occurring alongside prewar diplomacy. This hampered efforts to organize Iraq immediately after the fall of Saddam Hussein. Tehran had no such qualms, and broadcast Arabic-language television in Iraq months before the U.S. did.

Ideally, diplomatic and economic coercion will force Iran and North Korea to comply with international norms. But as Democrats conflate analysis with advocacy, they shortchange military preparations, a stick that would make it more likely that diplomacy will succeed.

By projecting good will onto our adversaries, Democrats also undermine containment and deterrence, the very strategies necessary to prevent war. After all, both are military strategies, consisting of deployments, arms sales to allies, and the long-term basing of U.S. troops abroad. Deterrence, as in the Cold War, requires that an adversary know beyond any doubt that using a nuclear weapon will result in a nuclear counterattack.

Containing Iran requires military outreach to the moderate Arab states, Israel and Azerbaijan. Containing China and deterring North Korea requires embracing--militarily, economically and diplomatically--Japan, Taiwan, India and Australia. Countering a resurgent Russia will require providing Poland, Romania and the Baltics the same support once given to West Germany. Realism requires embracing Colombia's recognition that Venezuela strongman Hugo Chávez's bark may foreshadow his bite.

Democrats may be right to criticize the Bush administration for being too optimistic in setting its foreign policy. The irony is that many Democrats in Congress are now making that very mistake themselves.

Michael Rubin is a resident scholar at AEI.