Iran's threats to close the vital Strait of Hormuz, its naval exercises in nearby waters, and the ominous increase in tensions over its nuclear weapons program all point to a dangerous year ahead.

Even worse, Iran's belligerent rhetoric and behavior today only foreshadow its behavior once it becomes a nuclear weapon-armed state.

Iran undoubtedly wants to avoid further economic sanctions, and is threatening the weak and unstable global economy to magnify the potential effect of any interruption in vital oil shipments from the Gulf region.

"It has long been clear that, absent regime change in Tehran, peaceful means will never persuade or prevent Iran from reaching its nuclear objective, to which it is perilously close."--John Bolton

But more importantly, Tehran is testing Western resolve, especially Washington's, as it draws ever closer to a nuclear capacity.

How should America respond? As the U.S. Fifth Fleet did, saying "any disruption will not be tolerated." Significantly, however, President Obama has not spoken, once again signaling to the ayatollahs that his heart just isn't into standing up to them.

The president's continuing lack of leadership in response to Iran's saber rattling brings to mind the October 1961 Berlin Crisis. There, just a few months after the communists began constructing the Berlin Wall to stop the hemorrhaging of refugees from East Germany, a confrontation developed at the Cold War's iconic Checkpoint Charlie, located between the U.S. and Soviet sectors in Berlin.

American Patton tanks, armed and ready, stood tube to tube with Soviet tanks just a few yards away, as Berliners and the world held their breath. At one point, President Kennedy telephoned his personal representative in Berlin, Gen. Lucius Clay, hero of the 1948-49 Berlin Airlift, to hear Clay's assessment.

Kennedy closed their conversation by saying, "Don't lose your nerve." Clay famously shot back: "Mr. President, we're not worried about our nerves. We're worrying about those of you people in Washington."

Iran today may not be equivalent to the Soviet Union in 1961, but then again, Barack Obama is no John F. Kennedy. Iran will be watching every American reaction, especially as it sees the European Union once again on the verge of opening negotiations over the nuclear weapons program.

The Tehran regime has made incalculable progress over the past decade by using the European obsession, shared in many U.S. circles, that there is some satisfactory negotiated settlement to Iran's nuclear aspirations.

While the prior negotiations droned on inconclusively, Iran gained precious time to advance its nuclear weapons program, enhance its political legitimacy by appearing diplomatically "reasonable," and fend off stricter sanctions. Every indication is that Iran will unlimber this successful strategy yet again.

Iran's ingenious, decade-long response to the West's naivete reveals the basic flaw in the whole sanctions approach, especially Obama's. Economic sanctions against Iran were once intended to force it to give up its nuclear weapons program, but now the president's aim is for sanctions simply to get Iran back to the negotiating table.

And once there, what will happen? The race, on the one hand, between Iran's scientific and technological progress toward achieving a deliverable nuclear weapons capability, and, on the other, the possibility that diplomacy or sanctions can stop Iran from achieving that objective, is now in its final stages.

It has long been clear that, absent regime change in Tehran, peaceful means will never persuade or prevent Iran from reaching its nuclear objective, to which it is perilously close.

Indeed, viewed dispassionately, advocating diplomacy or sanctions, and believing they will actually impede Iran's nuclear program, simply provides cover for Iran to do just that.

Unfortunately, Iran is paying attention to Obama's weakness, and the weakness of the Europeans, not to the Fifth Fleet's unequivocal statements. Once again, as in Berlin in 1961, it is those nerves back in Washington we should be worrying about.

John R. Bolton is a senior fellow at AEI