On June 6, 1968, presidential hopeful Senator Robert F. Kennedy planned to announce his intention to run for the White House during a keynote speech at the Ambassador Hotel in Los Angeles.

He had just beaten fellow Democrat Eugene Joseph McCarthy in the pivotal California primary and seemed to be on his way to The White House.

"We are a great country, an unselfish country and a compassionate country. And I intend to make that my basis for running... " he famously told the assembled guests and colleagues.

As he left the podium and prepared to exit the building through the crowded hotel kitchens, 24-year-old Sirhan Bishara Sirhan shot at Kennedy and the throng of campaign staff and guests.

Emilio Estevez's sprawling historical drama relives events leading up to the shooting through the eyes of 22 fictional characters whose fates intersect that fateful summer's night.

To say that Bobby is ambitious would be an understatement, cutting back and forth between the protagonists and their loosely entwined storylines, gradually bringing each emotional crisis into focus.

As the minutes tick by until Kennedy's speech, retired doorman John Casey (Anthony Hopkins) enjoys a leisurely game of chess in the hotel lobby with fellow retiree Nelson (Harry Belafonte), while celebrated singer Virginia Fallon (Demi Moore) drowns out thoughts of her unhappy marriage to husband Tim (Emilio Estevez).

Downstairs, resident hairdresser Miriam (Sharon Stone) learns a devastating secret about her husband, hotel manager Paul (William H Macy), and kind-hearted girl Diane (Lindsay Lohan) agrees to marry William (Elijah Wood) to save him from going to war.

In the kitchens, the scent of mutiny hangs on the air as the Latino workers, including bellboy Jose (Freddy Rodriguez), face insults from their bigoted boss (Christian Slater).

By the end of the night, some of these characters will be gunned down alongside Senator Kennedy, fighting for their lives in the white-hot glare of the media spotlight.

Estevez maintains a brisk pace and he has a good ear for dialogue, like the verbal jousting between John and Melson: "At least I don't have to get up three time a night to pee," quips one; "At least I get out of bed to have one!" retorts his pal.

The writer-director also achieves a pleasing balance between the light-hearted and the melancholy, mindful of the concerns of the era, like when Diane tells her fiancee, "If marrying you tonight keeps you from going to Vietnam, then it's worth it."

With so many storylines to flesh out in less than two hours, some of the characters come off worse than others; some should have been cut entirely - like the Kennedy volunteers who spend the afternoon on an LSD trip - to give other narratives more chance to develop.

Bobby is utterly engrossing but there's a nagging feeling that an even better film was well within Estevez's grasp.