An illuminating glimpse into the national-security debate was opened this week in Washington over Undersecretary of State John Bolton’s warning that Iran had threatened European diplomats that it would begin work on an atom bomb. Mr. Bolton issued his heads-up on Tuesday, saying that Iranian negotiators warned French, German, and British diplomats last month in talks in Paris that “they could enrich enough uranium for a nuclear weapon within a year and they could produce nuclear weapons within the range of our own assessment, which is a way of threatening the Europeans to get them to back down.” Not surprisingly, anonymous European diplomats quickly disagreed with this assessment. According to two news reports, they had discrepancies with Mr. Bolton’s account, but generally agreed that Iran’s deputy negotiator, Hoseyn Moussavian, stated that his country could begin uranium enrichment within a year.

It isn’t the first time Mr. Bolton’s tough words for proliferating dictators have earned him the scorn of critics – both inside and outside the Bush administration. Last year, North Korea’s official news agency called him “human scum.” Deputy Secretary of State Richard Armitage in 2002 launched a security clearance investigation against a member of his staff for the high crime of leaking unclassified documents to – get this – the Pentagon.

The latest criticism from Europe no doubt reflects the fact that the French, Germans, and British enjoy a robust trade with the Islamic republic, taking advantage of a market that has been closed to most American companies since Ayatollah Khomeini deposed the Shah in 1979.These three countries have also pursued a policy to engage the ruling mullahs in talks hoping to persuade them to open their facilities to International Atomic Energy Agency inspectors, a policy that has failed miserably, as evidenced by the agency’s regular reports on the Iranian nuclear program. Last month, Iran announced that it was breaking the IAEA seals on facilities that were closed after the international body learned Iran had undeclared sites for enriching uranium.

It’s also unsurprising that some American officials, likely residing in Mr. Bolton’s building, would not want this threat from Iran to come out. Last summer, it was Mr. Armitage who tacitly approved the European engagement initiative to forestall penalizing Tehran even as Mr. Bolton was pushing his European counterparts to recommend Iran’s transgressions be brought before the U.N. Security Council.

What is surprising is that Mr. Bolton was also pounced on by the pro-Kerry camp. One pro-Kerry blogger, Joshua Micah Marshall, promptly put up a long post Wednesday, saying “Mr. Bolton is probably more guilty than any other member of this administration of repeated, public misstatements, exaggerations and distortions of intelligence about Iran, Iraq, North Korea, Cuba and other countries regarding weapons of mass destruction and proliferation issues.”

To be sure, Mr. Bolton has had his share of disagreements with members of Washington’s professional intelligence bureaucracy. In one famous episode, the CIA went out of its way to scuttle Mr. Bolton’s testimony before the House International Relations Committee on Syria’s weapons of mass destruction program. In another case, President Carter, of all people, asserted – while on Cuban soil – that he saw no evidence for Mr. Bolton’s claims about Fidel Castro’s biological weapons programs. Few people at the time, or since, noted that in both these cases, Mr. Bolton’s remarks were approved by not only the State Department, but also the National Security Council.

In the latest case, it is amazing to see the Kerry camp crediting – as Mr. Marshall clearly did – anonymous French and German diplomats against the view of a sitting American undersecretary of state. By targeting Mr. Bolton as an individual, his critics conceal the fact that his public statements advance the policy of the president and his administration.

But just to make sure, I checked with Mr. Bolton’s office about the claim that Iran was prepared to enrich uranium within a year. In a written response to my query that was approved by the State Department, Mr. Bolton said, “Iran has suggested that it could possess nuclear weapons within three years, in addition the Iranians have said that they could have the capability within a year to enrich uranium to weapons grade levels, the critical step in a weapons program.”

Mr. Marshall calls Mr. Bolton’s practice of speaking his mind “deceitful and manipulative.” But Mr. Bolton to date is the only person in this story who has stood by his account of the Iranian meetings on the record. And when he was asked again about the issue, he stood by his original claim. The deceivers and manipulators in this case appear to be the anonymous diplomats and Kerry’s supporters seeking to advance a policy of engagement at the expense of Mr. Bolton’s reputation.