The shooting on Saturday night of a Secret Service agent at the White House Correspondents' Association dinner raises questions yet again about the protection afforded to America's political leaders at a time of increased political violence.

Hundreds of agents from several law enforcement agencies were tasked with protecting the annual bash, ?which U.S. President Donald Trump headlined this year.

Yet a suspect with a shotgun and other weapons managed to get just a ?floor above ?the Washington ballroom where an extraordinary concentration of Cabinet members, high-ranking lawmakers and celebrities were dining.