Amid the splendors of this ancient city on the Danube, the Iran nuclear talks are waltzing toward a fiasco. Russia's threat this week to change its position on the talks as payback for the West's negative reaction to the invasion of Ukraine could hardly make things worse.

The stated aim of the U.S. and its partners is to arrive at a grand bargain ensuring that Iran will not obtain nuclear weapons. The reality is that four months have passed since the U.S. and its partners struck an interim deal with Iran in Geneva proposing to work out a "long-term comprehensive solution." So far, under the negotiating mantra of "nothing is agreed until everything is agreed," the parties appear to be talking mainly for the sake of talking. According to a senior U.S. official at the round of meetings that wrapped up on Wednesday, "We understand each other's concerns."

That might work in a marriage, but this is a nuclear negotiation with a murderous, messianic state. Meanwhile, Iran without dismantling its nuclear infrastructure is enjoying a visible easing of sanctions and a celebrity comeback on the world stage.


Iran's Ambassador to the International Atomic Energy Agency, IAEA, Reza Najafi waits for the start of the IAEA board of governors meeting at the International Center in Vienna, Austria, Monday, March 3, 2014. Associated Press

In Vienna, the process has taken on a life of its own. And a comfortable life it is. The Austrian government, delighted to have swiped the nuclear talks from Geneva, is lavishing hospitality on all concerned. That includes the six world powers dubbed the P5+1—the U.S., Britain, France, China, Russia and Germanyled by European Union foreign-policy chief Catherine Ashton. Sharing the head table with Ms. Ashton at the main bargaining sessions, while publicly proclaiming Iran's "inalienable right" to enrich uranium, is the star of this show, Iran's chief nuclear negotiator and foreign minister, Mohammad Javad Zarif.

For the top negotiators, Austrian authorities have reserved one of Vienna's most magnificent hotels, the Palais Coburg. It is an impeccably restored 19th-century palace, with a royal portico, glittering chandeliers, duplex suites, big Jacuzzis and a lobby built around portions of the historic city walls. Mr. Zarif may be an envoy of the world's top terror-sponsoring state, but at the Vienna talks he is an honored guest; his hotel bill, along with Ms. Ashton's, is paid by the Austrian government.

For most of the talking, the negotiators prefer to hunker down at the Coburg. When necessary, and for photo-ops, they shuttle across town to the United Nations complex that houses the International Atomic Energy Agency. The IAEA has the job of monitoring Iran's compliance with its promise under the interim deal to ratchet back, for now, some elements of its nuclear program.

For reporters covering the talks, Austria is providing facilities in a huge convention center that adjoins the U.N. complex. The amenities include free cappuccino, cold drinks, hot meals and Austrian chocolates.

The staple largely missing from the venue is news. At the two major rounds of the Vienna talks to date, Mr. Zarif and Ms. Ashton have delivered what may be the shortest press conferences on record. Side by side, and flanked by the Iranian and EU flags, they have read brief prepared statements and then left without taking a question. Last month, they pronounced their talks "very productive." This month, in a text that ran to all of five sentences, they described their talks as "substantive and useful." The next round convenes in Vienna April 7-9.

Procedurally, all this counts as success. According to an EU spokesman, Ms. Ashton is "mandated to drive forward these negotiations" and "she is determined to do that." Such determination is the classic mistake of diplomats who become so invested in bargaining that they'll do anything to stay at the tablethus handing the advantage to the other side.

Take Russia, a member of the P5+1 team that Ms. Ashton's office and U.S. officials say is "united." This reflects the official urge to envelop Iran in a group hug, and so woo it to kindlier ways. But Russia has its own ideas about how to leverage this collective bargaining. Earlier this week, in response to Russia's grab of Ukraine's Crimea, the U.S. and EU imposed sanctions on several Russian officials. Russia's delegate to the Iran talks, deputy foreign minister Sergei Ryabkov, is now treating the talks not as a P5+1 team venture but as a point of leverage, threatening that Russia might retaliate by taking a separate stance from the other P5 parties on the Iran talks.

Iran has its own priorities as well. Tehran is so pleased with the partial easing of sanctions that its officials have been soliciting business and nuclear talent, from Tokyo to Europe's trade fairs. But for all the smiles at the talks, Iran is publicly stipulating that it won't dismantle its nuclear infrastructure, won't stop enriching uranium, won't abandon building the plutonium factory that is its heavy-water reactor near Arak, and won't stop developing ballistic missiles.

After the latest round ended, a senior U.S. official offered some procedural details on trying to haggle over or monitor the troubling facilities that Iran is refusing to give up. Speaking on background, the official described a process of identifying "gaps" in agreement among the negotiating parties, and working to "bridge those gaps"—a labor of such technical, political and diplomatic complexity that the official further compared it to "a Rubik's cube—you move one part, you affect the next."

Actually, it's not that complex. The equipment that Iran wants to keep isn't vital to an oil-rich and peaceful state. What Iran wants to keep are the elements of a nuclear arsenal. We've seen this game before, as U.S. diplomats navigated a maze of bridge-building maneuvers in nuclear talks with Iran's close ally, North Korea. In the end, it comes down to one big gap: The unavoidable fact that the Iranians aren't at the bargaining table to give up the bomb. They've come so they get a breather from sanctions while they finish building it.

Ms. Rosett is journalist-in-residence with the Foundation for Defense of Democracies, and heads its Investigative Reporting Project.