The souvenir-flinging man who attacked Italian premier Silvio Berlusconi joins a long list of gatecrashers, shoe-throwers and other security breachers who have embarrassed, bruised and even killed leaders worldwide.

As Berlusconi remained hospitalized Tuesday with a broken nose and two broken teeth, officials pledged to review security measures while deflecting mounting criticism of the premier's bodyguards.

A man with a history of psychological problems bloodied Berlusconi's face Sunday with a souvenir statuette of Milan's Duomo cathedral as the leader ventured into the crush of a political rally in the northern Italian city.

Italy's debate follows a familiar pattern: How much security is necessary when politicians seek to mingle with their public?

"The security failed because, as usual, Berlusconi did what you should never do: Seek direct contact with the crowd," said Andrea Nativi, a researcher at the Rome-based Military Center for Strategic Studies.

Public appearances and leaders who walk the streets unprotected are a magnet not just for terrorists but for political protesters, publicity seekers and people with psychological problems.

U.S. President Barack Obama has acknowledged "a screw-up" last month when two uninvited guests managed to get into a White House dinner and came into contact with the U.S. leader. Three uniformed Secret Service officers have been placed on leave while the security breach is investigated.

Last year's attempt by an Iraqi journalist to hit U.S. President George W. Bush with his shoes has been copied around the world. Victims include Chinese Premier Wen Jiabao, who was targeted by a student during a speech at Cambridge University.

The quality of security at the European Union was called into question last week when the environmental group Greenpeace managed to gatecrash a summit of the 27-nation bloc's leaders in Brussels. And in March an environmentalist threw a green liquid at Britain's Peter Mandelson, then the business secretary, as he arrived for a conference aimed at reducing carbon emissions.

Other breaches have proven deadly.

In the Netherlands, security around government officials was tightened following the assassination of populist politician Pim Fortuyn in 2002.

A year later, the murder of Swedish Foreign Minister Anna Lindh raised concerns over whether politicians should still feel free to stroll the streets of Stockholm with their families. The Swedish Security Police did increase bodyguards for politicians.

In 1990, Germany's then-Interior Minister Wolfgang Schaeuble was shot by a psychologically disturbed man during a political rally. Schaeuble, who today is Germany's finance minister, was left paralyzed from the waist down.