The ever-receding Obama “timelines” for Iran, the lack of a credible threat of serious sanctions, the secretary of state’s public disavowal of an ultimate option, and the persistent presidential silence on the entire topic make it likely that the Obama administration plans to pursue its “dual track” policy (ineffectual “engagement” and ineffectual “pressure”) until the policy is eventually overtaken by events. The fallback will be “deterrence” after Iran passes the nuclear threshold.

The irony is that the discrepancy between the Obama rhetoric and the Obama performance will doom deterrence as well. In his major campaign speech on Iran, Obama promised he would do “everything” in his power to stop Iran from acquiring nuclear weapons (in the speech as delivered, he actually repeated the word everything three times — the third time as a stand-alone sentence). Such weapons, he said both before and after he was elected, were “unacceptable.”

At her confirmation hearing, his secretary of state assured the Foreign Relations Committee that the Obama administration would employ whatever option was ultimately necessary to prevent Iran from acquiring nuclear weapons:

KERRY: … Is it the policy of the incoming administration, as a bottom line of our security interests and our policy, that it is unacceptable that Iran has a weapon under any circumstances and that we will take any steps necessary to prevent that or is it simply not desirable? I think, as you said, it’s in no one’s interest, which is less than the formation of the prohibition.

CLINTON: The president-elect has said repeatedly it is unacceptable. It is going to be United States policy to pursue diplomacy with all of its multitudinous tools to do everything we can to prevent Iran from becoming a nuclear weapons state.

As I also said, no option is off the table. So the president-elect has been very clear that it is unacceptable and that is our premise and that is what we are going to be basing our actions on.

In practice, Obama’s policy has been the one favored by Jimmy Carter’s national security adviser. In a March 5, 2009, hearing before the Senate Foreign Relations Committee on “US Strategy Regarding Iran,” Zbigniew Brzezinski urged a process with no public conditions or time limits, no assertions that force remained an option, and no statement that regime change was a goal. It was, he said, a process that might consume “years” — and warned we should not “become susceptible to advice from interested parties regarding how we are to proceed.” He made it clear that he meant Israel and its advice that a time limit should be set.

Senator Kerry asked if there wasn’t “an automatic timetable thrust on us” — because of “Iran’s own activities and Israel’s perception of those activities, as well as our own intelligence community’s interpretations of those activities.” Brzezinski answered, in essence, “no.” He cited the success of deterrence in the cases of the Soviet Union, China, and India and Pakistan:

The Indians and the Pakistanis have managed to deter each other — knock on wood — so far.

And deterrence, their experience with deterrence gives us some grounds for not being under tremendous time limits.

And, in any case, we know that deterrence is predictable if it works.

Deterrence is a great fallback position, knock on wood, if it works. So there is no need for tremendous time limits. They can just be points on a calendar.

But the effectiveness of deterrence ultimately depends on the credibility of the U.S. promise to come to the defense of states throughout the region — from Israel to Saudi Arabia — threatened by a nuclear Iran. That credibility may not survive a failure to prevent Iran from acquiring nuclear weapons.

Let me be clearer: once you have pledged to do “everything” to prevent an “unacceptable” occurrence, and then you allow it to occur, with no effort other than “smart” diplomacy, your next promise will not be believed. Your credibility will be gone.