Undersecretary of Defense for Policy Michele Flournoy said yesterday that military action against Iran is “off the table in the near term,” effectively walking back President Obama’s position that “all options are on the table.” She prefaced her statement with the banal assertion that “military force is an option of last resort,” which of course everyone knows and which implies by itself that force is off the table for now. But the United States nevertheless just softened its position again on Iran’s nuclear weapons program. If the president doesn’t return force to the table, it is going to stay off.

It seems as though the U.S. is trying to look irresolute and nonthreatening lately, but whether it’s on purpose or not, that’s what it looks like, and it isn’t helpful. A credible threat — simple deterrence — can make war somewhat less likely, just as police officers on the street make crime somewhat less likely. The Iranian government won’t cooperate with irresolute and nonthreatening enemies; it will steamroll irresolute and nonthreatening enemies.

Attacking Iran wouldn’t be my next step either. I’m entirely sympathetic to the administration’s aversion to it, and not only on behalf of American servicemen who may be injured or killed. I know lots of Iranians. All are decent people. Not a single one supports Tehran’s deranged government. All have friends and family back home, and it has been obvious for some time now that a very large percentage of their fellow citizens left inside the country feel the same way. I don’t want to see any of these people get killed, especially if they’re killed by us. The very idea fills me with horror.

And that’s before factoring in the Israelis and Lebanese who would also be killed if the war spreads to the Levant — a likely event. I spend enough time in the Middle East that I could even end up in a bomb shelter myself.

We have to be realistic, though. There is only the smallest of chances that the Iranian government will mothball its nuclear weapons program if it does not feel some serious heat. Some people can only be disarmed at gunpoint, and that’s true of nearly all belligerent people.

Yet “off the table” has become the new normal. It will remain the new normal until further notice. The United States looks like it’s in retreat. Hardly anyone in the world believed President Obama would ever order a strike even before this most recent of climb-downs.

The administration seems to forget that threatening military action doesn’t necessarily mean we have to go through with it, that we want to go through with it, that we yearn to go through with it, or that we’re warmongers. Look at Taiwan. It exists independently of China only because the United States has made it clear that an invasion of Taiwan would be punished severely. Chinese leaders find the threat credible and have therefore backed off to let Taiwan live. The U.S. doesn’t have to pull the trigger. It’s enough just to say don’t even think about it.

Former Communist countries in Eastern Europe were similarly placed under Western military protection after the collapse of the Soviet Union. Moscow understands perfectly well that its liberated subjects are to be left alone — or else. Saying “hands off Lithuania” by bringing the country into NATO wasn’t cowboy behavior. It was prudent and wise, and it keeps the peace. Russia didn’t like it and still doesn’t like it, but it hasn’t gotten anyone killed.

Deterrence prevents armed conflict by making it clear to the other side that a war would be too costly and shouldn’t be tried. The reverse is true, too. Under certain conditions, war becomes more likely if it looks like there won’t be serious consequences.

Russia invaded Georgia a few years ago, but there is almost no chance that would have happened if Georgia had been a member of NATO. Russia would not have even considered it. The retaliation would have been devastating.

Deterrence might not work with Iran, but it’s even less likely to work if it’s downgraded, put on hold, or smells like a bluff. It’s all but certain to fail once the regime has nuclear weapons and can, short of incinerating cities with weapons of genocide, pretty much do whatever it wants.