Getting tough in Karbala?

In what world is this a smart move?

The American military attacked a mosque in this holy city [Karbala] on Tuesday in its largest assault yet against the forces of the young rebel Shiite cleric Moktada al-Sadr, even as the first signs emerged of a peaceful resolution to the five-week-long standoff with him.

The strike on the Mukhaiyam Mosque brought hundreds of American soldiers and their armored vehicles to within a third of a mile of two of the holiest sites in Shiite Islam, the shrines of the martyrs Hussein and Abbas. A building behind the mosque was fired on, detonating a huge weapons cache, and soldiers stormed the mosque, chasing insurgents out into a hotel and alley. The number of casualties could not be immediately determined.

I know the US military wants to send a message of "strength" following the debacle of last month, particularly towards Al Sadr, but is this the right way to go about doing that?

There's already a strong, vibrant resistance in Sunni-dominated Fallujah. Does the military want to reignite the flames amongst a broad swath of Shiites, too?