In 1982, Argentina’s military junta invaded the Falkland Islands, a self-governing British Overseas Territory in the South Atlantic. British Prime Minister Margaret Thatcher sent a liberation task force to the islanders’ aid. Some 255 British servicemen laid down their lives in the conflict, but with logistical support from the United States, the British forces emphatically defeated the Argentines.

Thirty years on, Argentina is again threatening the Falklands, with a campaign of intimidation aimed at isolating the 3,000 inhabitants. Over the past 18 months, the Argentine government has attempted a partial maritime blockade, in some instances boarding European fishing vessels operating under Falkland Island licenses, and turning away cruise ships headed for the Falklands. Argentina’s populist President Cristina Fernandez also has made repeated demands for the Falklands to be handed over by the British and issued numerous inflammatory statements attacking the U.K. Faced with mounting economic woes and sinking popularity at home, Ms. Fernandez has rekindled nationalist sentiment, placing the Falklands issue at the heart of her agenda.

In the face of growing Argentine provocation, the British government has reinforced the defenses of the islands, deploying another infantry company with recent combat experience in Afghanistan’s Helmand province, adding to the 1,200 troops already there. It also plans to send another warship to support the Royal Navy destroyer that already patrols the waters around the islands. Prime Minister David Cameron has vowed to defend the islands and has made it clear that “the future of the Falkland Islands should be determined by the Falkland Islanders themselves.” On March 10 and 11, inhabitants of the Falklands will vote in a referendum to decide whether they wish to retain their current political status as an overseas territory of the United Kingdom. They are expected to vote overwhelmingly in favor of maintaining their ties to Britain.

Argentina, however, refuses to recognize the referendum. Vice President Amado Boudou has branded the Falkland Islanders a “band of pirates.” Buenos Aires is not alone in its approach — appallingly, the U.S. State Department has so far refused to say it will recognize the results of the Falklands vote.

At a news conference last June, State Department spokeswoman Victoria Nuland repeatedly reiterated the U.S. position of “neutrality” when asked about the referendum, and declined to acknowledge the self-determination of the Falkland Islanders.

Far from remaining “neutral,” the Obama administration has openly backed Ms. Fernandez’s calls for U.N.-brokered negotiations over the sovereignty of the Falklands, and has steadfastly refused to stand with London on the issue. It has referred to the islands in the past by their Argentine name, “Malvinas,” and has signed on to Organization of American States resolutions supporting Argentina’s demands for a negotiated settlement, no doubt in an effort to appease Latin American opinion.

All of this has been a slap in the face for London, at a time when several thousand British troops are fighting alongside U.S. forces on the battlefields of Afghanistan. This senseless policy also places President Obama on the same side as America-hating regimes such as Hugo Chavez’s Venezuela and Daniel Ortega’s Nicaragua, regional allies of Ms. Fernandez’s flailing government.

As the Falklands referendum approaches, the Obama administration should strongly support the Falkland Islanders’ right of self-determination and condemn Argentina’s growing aggression. It also make must clear that it stands firmly with America’s closest friend and ally. As Margaret Thatcher once noted, the “special relationship” is vital to both U.S. and British interests, a message that Mr. Obama should heed.

“Whatever people say, the special relationship does exist, it does count and it must continue, because the United States needs friends in the lonely task of world leadership,” Mrs. Thatcher noted. “More than any other country, Britain shares America’s passionate commitment to democracy and willingness to stand and fight for it. You can cut through all the verbiage and obfuscation. It’s really as simple as that.”

- Nile Gardiner, a former aide to Lady Thatcher, is the director of the Margaret Thatcher Center for Freedom at the Heritage Foundation.