Pope Benedict XVI's comments on religious radicalism are another sign of his intention to bring his voice into one of the world's most critical showdowns: Islam's internal struggles between moderates and extremists. The remarks — tucked into an address at a German university where he formerly taught theology — were interpreted by many experts in interfaith relations as a signal that the Vatican is staking a new and more demanding stance for its dealings with the Muslim world. Benedict, they say, appears to increasingly view the West's confrontation with radical Islam as a fateful moment in history that demands the...