The promotion of Gen. David Petraeus is another ominous sign that the Bush administration may attack Iran.

President Bush is nominating Petraeus, Commanding General of the Multi-National Force in Iraq, to replace Adm. William Fallon as head of Centcom: U.S. Central Command, which oversees the wars in Afghanistan and Iraq.

Fallon was forced to resign last month after his outspoken opposition to an attack on Iran. Petraeus, by contrast, has been heating up the rhetoric against Iran.

“Iran has fueled the violence in a particularly damaging way through its lethal support to the special groups,” Petraeus testified to Congress in early April. Those special groups (meaning, the militias) pose the biggest threat to the United States, he added.

He blamed Iran for the rocket attacks on the Green Zone, and he warned, “We should all watch Iranian actions closely in the weeks and months ahead.”

Petraeus’ boss issued a warning of his own. “The regime in Tehran also has a choice to make,” Bush said on April 10. “If Iran makes the right choice, America will encourage a peaceful relationship between Iran and Iraq. If Iran makes the wrong choice, America will act to protect our interests, and our troops and our Iraqi partners.”

But neither Petraeus nor Bush mentioned the role Iran played in mediating a ceasefire between the Iraqi government and Shiite militias in Basra last month. Rather than blaming Iran, they should have been thanking it.

Bush has also continued to hype Tehran’s nuclear threat. Instead of acknowledging the December 2007 National Intelligence Estimate, which concluded that Iran had suspended its nuclear weapons program, Bush criticized the report. In a March 20 interview with U.S.-funded Radio Farda, which broadcasts into Iran, Bush insisted that President Mahmoud Ahmadinejad’s government seeks “a nuclear weapon to destroy people — some in the Middle East.”

If the run-up to the Iraq War serves as an example, with the administration dismissing facts about Iraq that contradicted its case for regime change, Americans should remain concerned about a possible U.S. strike on Iran.

Bush could justify an attack on Iran’s military or nuclear facilities by claiming to protect U.S. troops in Iraq against Shiite militias with links to Tehran. Iran could retaliate by not only threatening those troops, but also by inspiring Hezbollah in Lebanon to mobilize jihadists against Israel and the United States.

The United States cannot afford to be bogged down in another war. The projected cost of the Iraq War has reached $3 trillion. To date, more than 4,000 Americans have been killed there.

Meanwhile, Afghanistan remains unstable, and any attack by the United States on Iran would distract the Pentagon from its task of controlling Afghanistan and tracking down Osama bin Laden.

Such an attack would also inflame anti-American sentiment throughout the Muslim world. Already, according to a recent Arab Public Opinion poll, 83 percent of those polled in Saudi Arabia, Egypt, Jordan, Lebanon, Morocco and the United Arab Emirates hold an unfavorable view of the United States.

A more constructive U.S. posture should elevate diplomacy and negotiations with Iran. Bush, along with the current presidential aspirants, should review the Iraq Study Group’s recommendations.

Here’s one worth testing out: The United States should “engage directly” with Iran to “obtain their commitment to constructive policies toward Iraq and other regional issues.”

The alternative is just too hazardous.

Farrah Hassen, a Syrian-American, is the Carol Jean and Edward F. Newman Fellow of the Institute for Policy Studies in Washington, D.C. She can be reached at pmproj@progressive.org.