[GOP-Pat]

I don't understand how a grenade could have been thrown on the stage with him. He was surrounded with a bullet proof screen.

From a news article:
Ongoing fights in violent separatist regions, military campaigns against terrorists in the Pankisi Gorge and the recent abductions of foreigners presented security challenges that required Bush to deliver his open-air speech from a podium surrounded by a high wall of a clear bulletproof screen with sharpshooters on rooftops surrounding the square.
http://aolsvc.news.aol.com/news/article.adp?id=20050506160909990014

[MJY1288]

In a security video, authorities think they saw who threw the DUD, it was Harry Reid :-)

They say his bomb throwing came up short and had no effect :-)