We’ve heard this quickening drumbeat before. Last time, it led to the tragic invasion and occupation of Iraq. This time, if we let the drummers provoke us into war with Iran, the consequences will likely be far worse.

Rat-ta-tat-tat. Weapons of mass destruction. Boom-shakka-boom. A madman in charge. Thump-thump-thump. Mushroom clouds.

Tune out the anxiety-inducing percussion and think for a minute. Yes, there are good reasons to be concerned about the Iranian nuclear program. But it doesn’t follow that launching a military attack — or providing support for an attack by Israel — would necessarily be effective, let alone wise. The evidence suggests it would be neither.

Obviously, Iranian officials are lying when they say that their nuclear program is entirely for peaceful purposes. But it is clear that Iran does not yet have the ability to build a nuclear weapon — and unclear whether the Iranian government, if and when it does achieve that capability, will take that final provocative step.

Covert operations believed to have been carried out by Israeli intelligence agents, perhaps with U.S. assistance — a diabolically clever computer virus that crippled many of Iran’s enrichment centrifuges, along with the targeted assassinations of key Iranian scientists — have significantly slowed Iran’s progress toward being able to make a bomb. It is reasonable to assume that such actions, and their effectiveness, will continue.

But let’s ...