Presumptive Republican presidential nominee Sen. John McCain (R-AZ) listens to U.S. President George W. Bush at the National Catholic Prayer Breakfast in Washington on April 18, 2008. (UPI Photo/Yuri Gripas)

MOSCOW, April 28 (UPI) -- The latest meeting in Shanghai of the six international mediators in the Iranian nuclear issue has been a fiasco, as is suggested by the meager news reports.

The participating countries, the five permanent U.N. Security Council members plus Germany, again failed to find common ground. What happened?

Sen. John McCain, R-Ariz., the Republican front-runner in the U.S. presidential race, could have caught a glimpse of what was happening at that meeting behind closed doors.

In an interview this week with ABC News, McCain emphasized his belief in the decisive role of tough sanctions in resolving the problem of Iran's nuclear program. He favors tough sanctions against the Islamic republic to force it to halt its uranium enrichment program -- which has not only aroused international concerns, but made the world doubt it might be for purely peaceful purposes as Iran claims. The senator said the sanctions up until now have never been sufficiently tough, as the Russians blocked all efforts of Washington and the European Union in the Security Council.

McCain's position in favor of toughening sanctions against Iran is not news. Moreover, for some reason he clearly echoed the ideas considered by Russian and U.S. experts on Iranian nuclear problems who met in Moscow on April 14 as part of the Luxembourg Forum.