Associated Press

As U.S. President Barack Obama intensifies his efforts to garner international support for fresh U.N. sanctions against Iran, Tehran is quietly putting its own measures in place for renewed confrontation with the West. Watching how a conventionally armed Iran manages to destabilize the entire region only serves to underline how dangerous a nuclear-armed Iran would be.

For all of President Mahmoud Ahmadinejad’s public bluster, the Iranian regime likely feels threatened by the prospect of further sanctions—so much so that it has now embarked on a well-organized and coordinated effort to attack or undermine Western interests throughout the region. The most sinister trend is the revival of Iran’s international terrorist infrastructure, which is evident in neighboring Afghanistan where NATO intelligence officers have reported a marked increase in cooperation between Iran’s Revolutionary Guards and Taliban insurgents.

…With so much Iranian activity taking place throughout the region, the message is clear: Any attempt by the West to increase the pressure on Iran over its nuclear program will result in an explosion of violence throughout the Middle East and beyond. The problem is that doing nothing about Tehran’s nuclear ambitions would be even more dangerous.

Mr. Coughlin is executive foreign editor of London’s Daily Telegraph. The updated edition of his book “Khomeini’s Ghost” has just been published by Ecco.