Suppose a country funds, arms, and trains on its soil a force to infiltrate and destabilize its neighbor with a campaign of ethnic cleansing.

* Suppose a country funds, arms, and trains on its soil a force to infiltrate and destabilize its neighbor with a campaign of ethnic cleansing. Would you call that an act of war? Sensible people, of course, would. But American politicians have resisted calling Iran's material support for Shiite terrorist groups exactly what it is: an act of war against Iraq, and the United States. Following a trip to Baghdad, Sen. Joseph Lieberman broke this silence, saying during a Face the Nation appearance, "I think we've got to be prepared to take aggressive military action against Iranians to stop them from killing Americans in Iraq." Democrats' "netroots" worked themselves into a predictable frenzy. Wesley Clark derided Lieberman's "saber rattling." And Harry Reid condescended--"I know Joe means well"--before arguing that the proper response to these acts of war is diplomacy. Diplomacy, of course, has been a repeated failure with Iran. Four years after Iran's nuclear program was farmed out to European diplomats, we have nothing to show for it. And we have already talked directly to the Iranians--breaking three decades of policy --about their stoking of mayhem in Iraq. It is naive to think diplomacy will bear fruit now, especially when the "see no evil" posture on Iran allows it to pay no price for underwriting violence in Iraq.