London

“IT is not going too far to say that American foreign policy has become completely subservient to tactical domestic political considerations.”

This stern verdict comes from Vali Nasr, who spent two years working for the Obama administration before becoming dean of the Johns Hopkins School of Advanced International Studies. In a book called “The Dispensable Nation,” to be published in April, Nasr delivers a devastating portrait of a first-term foreign policy that shunned the tough choices of real diplomacy, often descended into pettiness, and was controlled “by a small cabal of relatively inexperienced White House advisers.”

Nasr, one of the most respected American authorities on the Middle East, served as senior adviser to Richard Holbrooke, Obama’s special representative to Afghanistan and Pakistan until his death in December 2010. From that vantage point, and later as a close observer, Nasr was led to the reluctant conclusion that the principal aim of Obama’s policies “is not to make strategic decisions but to satisfy public opinion.”

In this sense the first-term Obama foreign policy was successful: He was re-elected. Americans wanted extrication from the big wars and a smaller global footprint: Obama, with some back and forth, delivered. But the price was high and opportunities lost.

“The Dispensable Nation” constitutes important reading as John Kerry moves into his new job as secretary of state. It nails the drift away from the art of diplomacy — with its painful give-and-take — toward a U.S. foreign policy driven by the Pentagon, intelligence agencies and short-term political calculus. It holds the president to account for his zigzags from Kabul to Jerusalem.

It demonstrates the emasculation of the State Department: Nasr quotes Admiral Mike Mullen, former chairman of the Joint Chiefs of Staff, telling him of Hillary Clinton that, “It is incredible how little support she got from the White House. They want to control everything.” And it paints a persuasive picture of an American decline driven not so much by the inevitable rise of other powers as by “inconsistency” that has “cast doubt on our leadership.”

Nowhere was this inconsistency more evident than in Afghanistan. Obama doubled-down by committing tens of thousands more troops to show he was no wimp, only to set a date for a drawdown to show he was no warmonger. Marines died; few cared.

He appointed Holbrooke as his point man only to ensure that he “never received the authority to do diplomacy.” Obama’s message to President Hamid Karzai of Afghanistan was: “Ignore my special representative.” The White House campaign against Holbrooke was “a theater of the absurd,” Nasr writes. “Holbrooke was not included in Obama’s videoconferences with Karzai and was cut out of the presidential retinue when Obama went to Afghanistan.”

The White House seemed “more interested in bringing Holbrooke down than getting the policy right.” The pettiness was striking: “The White House kept a dossier on Holbrooke’s misdeeds and Clinton kept a folder on churlish attempts by the White House’s AfPak office to undermine Holbrooke.”

Diplomacy died. Serious negotiation with the Taliban and involving Iran in talks on Afghanistan’s future — bold steps that carried a domestic political price — were shunned. The use of trade as a bridge got scant attention. Nasr concludes on Afghanistan: “We are just washing our hands of it, hoping there will be a decent interval of calm — a reasonable distance between our departure and the catastrophe to follow.”

In Pakistan, too nuclear to ignore, the ultimate “frenemy,” Nasr observed policy veering between frustrated confrontation and half-hearted attempts to change the relationship through engagement. “The crucial reality was that the Taliban helped Pakistan face down India in the contest over Afghanistan,” Nasr writes. America was never able to change that equation. Aid poured in to secure those nukes and win hearts and minds: Drones drained away any gratitude. A proposed “strategic dialogue” went nowhere. “Pakistan is a failure of American policy, a failure of the sort that comes from the president handing foreign policy over to the Pentagon and the intelligence agencies.”

In Iran, Nasr demonstrates Obama’s deep ambivalence about any deal on the nuclear program. “Pressure,” he writes, “has become an end in itself.” The dual track of ever tougher sanctions combined with diplomatic outreach was “not even dual. It relied on one track, and that was pressure.” The reality was that, “Engagement was a cover for a coercive campaign of sabotage, economic pressure and cyberwarfare.”

Opportunities to begin real step-by-step diplomacy involving Iran giving up its low-enriched uranium in exchange for progressive sanctions relief were lost. What was Tehran to think when “the sum total of three major rounds of diplomatic negotiation was that America would give some bits and bobs of old aircraft in exchange for Iran’s nuclear program”?

On Israel-Palestine, as with Iran, Obama began with some fresh ideas only to retreat. He tried to stop Israeli settlement expansion. Then he gave up when the domestic price looked too high. The result has been drift.

“The Dispensable Nation” is a brave book. Its core message is: Diplomacy is tough and carries a price, but the price is higher when it is abandoned.