In recent weeks, four key developments have clicked in to edge Iran and Israel much closer to a military denouement, with profound consequences for American oil that the United States is not prepared to meet.

• Iran has proven it can successfully launch a satellite into outer space, as it did on Feb. 2. Tehran claimed to the incredulity of Western governments that the satellite was to monitor earthquakes and enhance communications. Few believe that. And Tehran plans three more satellites this year.

• The International Atomic Energy Agency reported last week that it had underestimated Iran’s nuclear stockpile by about one-third. The watchdog group now confirms Iran possesses 2,227 pounds of nuclear material, sufficient to create at least one nuclear bomb.

• Iran has ramped up its enrichment program with thousands of new homegrown, highly advanced centrifuges. Iran now has 5,400 of the 6,000 centrifuges it wants to speed the enrichment of weapons grade material. American policymakers are now convinced that Iran, despite all protests and charades, is in a mad dash to create a deliverable nuclear weapon.

• Benjamin Netanyahu is determined to take action before — not after — Iran achieves its nuclear potential. This creates a volatile, hair-trigger situation. Hence, the end game is now vastly closer today than it was in mid-January, when many believed Israel might take action during the lame-duck interregnum.

Israeli countermeasures to date have included a massive international covert program of equipment sabotage, assassination of key nuclear personnel and a vibrant diplomatic offensive.

But all these efforts combined amount to nothing more than delay tactics as Iran is irrevocably determined to achieve a nuclear weapon as fast as possible. Many believe such a weapon will be used to fulfill its prediction that Israel will soon be wiped off the map.

The thinking was that Israel had only a narrow window in which to strike first, before Iran took final delivery of the S-300 advanced air defense system from Russia. But now, not wanting to accelerate an Israeli response, Russia has announced a pause in deliveries.

Iran, of course, has repeatedly threatened to counter an attack by closing the Strait of Hormuz, as well as launching missiles against the Ras Tanura gulf oil terminal and bombarding the indispensable Saudi oil facility at Abqaiq, responsible for some 65 percent of Saudi production — immediately shutting off 40 percent of all seaborne oil, 18 percent of global oil and some 20 percent of America’s daily consumption.

America’s oil vulnerability has been back-burnered due to the economic crisis and the plunge in gasoline prices. However, an interruption would not restore prices to that of last summer, but probably zoom the pump cost to $20 per gallon.

American oil vulnerability in recent months has escalated precisely because of oil’s drop to $35 to $40 a barrel. At that price, America’s No. 1 number one supplier, Canada, which supplies some 2 million out of 20 million barrels of oil a day, cannot afford to produce; Canadian oil sand petroleum is not viable below $70 a barrel. Much of Canada’s supply progress has already been cancelled or indefinitely postponed. America’s strategic petroleum reserve can only keep our country moving for approximately 57 days.

The question of when and how this end game will play out is not known by anyone. Israeli leaders wish to avoid military pre-emption at all costs if possible. But many feel the military moment must come; and when it does, it will be swift, highly technological and in a twinkling of an eye.

But as one informed official quipped, “Those who know don’t talk. Those who talk don’t know.”

Edwin Black is the author of “IBM and the Holocaust” and the new book “The Plan: How to Save America When the Oil Stops — or the Day Before.”