A clutch of former intelligence chiefs and diplomats have joined forces to press for more stringent sanctions against Iran to deter the Islamic republic from pursuing its nuclear programme, warning that the alternative is a military conflict.
They include Meir Dagan, a former director of the Mossad, former CIA chief James Woolsey and former chief of staff of the British armed forces Charles Guthrie. Dagan is already on record as saying an Israeli military strike on Iran is "the stupidest thing I ever heard".
In a comment piece for the Wall Street Journal, they argue that "the world faces a stark choice. Our near future carries the risk of a military conflict with Iran, or a nuclear arms race in the already volatile Middle East.
"It is still possible to avoid these outcomes, but only if like-minded nations act immediately to deliver a potentially decisive economic blow to the regime."
Existing sanctions are having a tangible impact, say the authors, citing the "freefall" of Iran's currency, the rial. But now the international community must "truly isolate the regime".
They say this means "passing the most robust sanctions against Iran in history".
They propose four measures:
all Iran's financial institutions must be severed from the international banking system;
Iran should be denied access to international shipping;
companies must be required to disclose all investments and business transactions in Iran;
insurance companies operating in Iran should be prohibited from doing business in the US and EU.
"History has made clear that the regime will never change course due to half measures; only serious steps like we've outlined have a chance of success. With Iran finally feeling real impact from international sanctions, now is the time to increase the pressure," write the authors.
The article comes ahead of next week's talks in Baghdad between Iran and the US, Russia, China, France, Britain and Germany. Its other signatories are August Hanning, former head of Germany's intelligence agency; Kristen Silverberg, a former US ambassador to the EU; and Mark Wallace, a former US ambassador to the UN.
Dagan and other former Israeli military and intelligence figures have infuriated those in favour of military action by speaking out against a strike. Last month, the former head of Shin Bet, Israel's internal security agency, said he had no faith in prime minister Binyamin Netanyahu and defence minister Ehud Barak to conduct a war. He described the pair as "messianic".