WASHINGTON — On Dec. 31, just hours before a New Year’s Eve celebration, President Barack Obama signed the National Defense Authorization Act for Fiscal Year 2012. Section 1245 of the law contains language providing authority to impose economic sanctions on Iran in order to deter the ayatollahs from acquiring nuclear weapons.

White House efforts to have the sanctions provision stripped from the bill failed, and the measure became law with a quiet flourish of the presidential pen. Ever since, Washington and Tehran have been waging a war of words. None of this works to the advantage of the American people. Here’s why.

Tehran replied to the “new sanctions” — which have yet to be imposed — with a series of military exercises and threats to close the narrow Strait of Hormuz, through which passes nearly 20 percent of the world’s supply of petroleum. In a now familiar rhetorical tit for tat, the Obama White House propaganda mill responded by leaking that POTUS had sent a “clear and unequivocal message” through a “secret channel” that cutting the flow of oil would be “unacceptable.” Defense Secretary Leon Panetta and others took to the airwaves and print outlets to talk about Iranian nukes and closing the strait as a “red line” for the U.S.

This week, we learned from Tehran that Obama’s “secret message” was addressed to Iran’s supreme leader, Ayatollah Ali Khamenei. According to Ali Motahari, a mouthpiece for the theocrats, “the first part of the letter contains threats, and the second part contains an offer for dialogue.” Iran’s government-run Fars News Agency quoted Motahari as saying, “In the letter, Obama called for direct talks with Iran.”

The White House has neither confirmed nor denied the contents or even the delivery of such a missive. On Thursday, Obama administration spokesman Tommy Vietor told reporters, “The U.S. remains committed to engaging with Tehran and finding a diplomatic solution.” If any of this is true, nothing has changed in nearly three years of the Obama administration — except that Iran is now much closer to acquiring nuclear weapons.

According to U.S., European and Israeli intelligence sources, Iran will begin producing enriched uranium at the deep-underground, heavily protected Fordo nuclear facility, near the city of Qom, “in a matter of weeks.” Last November, inspectors from the International Atomic Energy Agency reported indications of “advanced enrichment for potential nuclear weapons use” at Iran’s Nantaz and Bushehr nuclear sites.

The Obama administration’s naive infatuation with “direct talks” and its belief in equivocal sanctions are at odds with reality. Four years of United Nations sanctions have produced no results. The “open hand” and “mutual respect” Obama offered Tehran in 2009 have yielded nothing. Last year, the so-called negotiations — with the U.S., Britain, Germany, France, Russia and China on one side of the table and the Iranians on the other — collapsed in Istanbul when Tehran refused to continue talking as long as any sanctions remained in place.

Though new sanctions — such as those mandated by the National Defense Authorization Act — appear to be onerous, the deterrent effects on Iranian nuclear ambitions are doubtful at best. According to the new law, on Feb. 29, the Obama administration is supposed to bar international banks that do “any significant financial transaction with the Central Bank of Iran” from access to U.S. banking institutions. But enforcement is up to the O-Team — an outfit not exactly known for adhering to the letter of the law.

And now some of our “allies” are getting cold feet on cutting their access to Iranian oil; the second phase of NDAA sanctions are due to kick in June 28. No one really expects Russia, China, Venezuela, North Korea or Cuba to play ball. But this week, France, India, Turkey and South Korea all protested that the new sanctions could adversely affect their economic recovery from a lengthy recession and that they need “more time” to find alternative sources to replace the Iranian oil they have already contracted to buy.

Time is what the Iranians want most of all. Like the North Koreans, who built nuclear weapons while starving their own people, the ayatollahs have figured out how to build such devices. Their determination to do so was unabated by the Stuxnet computer worm. They have not been stopped by the violent, untimely demise of five nuclear experts. All Tehran’s masters of deceit and delay need is time. They knew before we did that the threat of supposedly harsh sanctions was undercut by an election-year diplomatic gambit for direct negotiations in Obama’s “secret letter.”

The effect of White House ambivalence and incompetence is that Iran — the world’s foremost purveyor of terror — will acquire nuclear weapons in the days ahead. When that happens, reopening the Strait of Hormuz to ensure the world’s supply of energy will become a perilous affair.

On Jan. 18, the Obama White House doubled down on this lunacy and pulled the plug on the Keystone pipeline connecting oil fields in western Canada to refineries in Texas. In a blatant pander for votes from environmental radicals, Obama sold out hopes for improving U.S. energy security, guaranteed higher fuel costs for all of us and eliminated tens of thousands of jobs. All this should be a red line for American voters.