The public slaughter of American journalist James Foley by the Islamic State in Iraq and the Levant has raised wrenching questions about the U.S. government's long-standing policy of refusing to pay ransoms to terrorists. What really deserves scrutiny is the willingness of European governments to meet such demands.

The millions of dollars in ransoms paid to ISIL effectively subsidized Foley's kidnapping and execution, not to mention the terrorists' swath of death and destruction across Syria and Iraq.

The U.S. Treasury Department has called kidnapping for ransom "today's most significant source of terrorist financing." Ransoms paid to Al-Qaida and its direct affiliates since 2008 amount to about $165 million. A separate accounting by the New York Times put the total for last year alone at $66 million.

The willingness of governments to pay for their citizens' release has only upped terrorist demands, with deadly results.

So far, most of the international community has yet to live up to pledges made through the United Nations in 2009 and the Group of Eight in 2013 not to pay ransoms. Two exceptions have been the U.S. and Britain. Although that stance has resulted in the murder of people such as Foley and Edwin Dyer, a 61-year-old British citizen killed by Al-Qaida in 2009, it has also made U.S. and British citizens less lucrative, and thus less frequent, targets.

By contrast, the Times estimates that nations such as France, Austria, Spain and Switzerland account for more than half of those taken captive by Al-Qaida and its affiliates in the past five years.

Paying a ransom to a terrorist group will always be tempting, especially to governments that want to be able to reassure their citizens about their safety. But every euro paid to save a hostage's life potentially goes to capture or kill another. That's a recipe for perpetual mayhem.

Is it too much to ask that, as champions of collective security, NATO's members swear off ransom payments that serve only to endanger the lives and interests of all its members?