By Bob Tourtellotte

LOS ANGELES — They are a bloody dictator, diamond smuggler, crack-smoking school teacher, lecherous old man, and self-centered dad. But when it comes to winning an Oscar for best acting, the more human flaws, the better.

This year’s Oscar nominees for best lead actor — Forest Whitaker, Leonardo DiCaprio, Ryan Gosling, Peter O’Toole and Will Smith — portray characters so fault-ridden that they are hard not to like. In fact, Oscar loves them.

Last year, Philip Seymour Hoffman cruised to his Academy Award victory emphasizing the dark, manipulative side of writer Truman Capote’s otherwise flamboyant personality in "Capote." The year before, Jamie Foxx showed audiences that soul singer Ray Charles was also a heroin-addicted woman chaser in "Ray."

The favorite this year to win the Oscar, which will be given out by the Academy of Motion Pictures Arts and Sciences on February 25, is Whitaker playing the blood-thirsty late Ugandan dictator Idi Amin in "The Last King of Scotland."

He prepared to play the brutal ruler — under Amin’s regime more than 300,000 people were tortured, killed or "disappeared" — by talking to former Ugandan generals and Amin family members and visiting Amin’s old haunts. He even sat in Amin’s chair.

"I completely committed to it," Whitaker said. "I slept with him."

Of course, the sleeping part was figurative — Amin died in 2003. But actors, especially the Oscar-nominated kind, have a flair for drama.

Along with drama, Oscar likes a good laugh, which may help Gosling.

When asked what he did to research his role as a drug-addicted grade school teacher in "Half Nelson," Gosling dead-panned to Reuters, "I smoked a lot of crack."

He was joking.

DiCaprio, playing a gem smuggler in "Blood Diamond," about how the jewel trade fueled civil war and child soldiers, tossed away the research, went to Africa and hung out with the locals who actually did the dirty work.

But it’s unlikely Whitaker will face stiff competition from either Gosling or DiCaprio, Oscar watchers said.

The thinking is low-budget movie "Half Nelson" was not seen by enough people for Gosling to get the necessary votes.

"Blood Diamond" was a major Hollywood production but it struggled at US box offices with a modest gross of just $55 million. That fact spells trouble for DiCaprio because Oscar voters like blockbuster ticket sales from big-studio movies.

O’Toole, 74, stands the best chance of beating Whitaker, because Oscar voters tend to favor screen veterans regarded as long overdue for an award, pundits say.

The Irish performer, who shot to fame as the star of "Lawrence of Arabia," has received eight nominations as best actor in the past four decades without yet winning. In "Venus," he plays an elderly actor with a love of whiskey and a crush on a younger woman.

"No star has ever lost eight times," said Tom O’Neil, columnist at the Oscar Web site TheEnvelope.com.

That leaves Smith in the $161 million box office hit "The Pursuit of Happyness," as Whitaker’s other main rival.

He plays a dud of a dad who plunges himself and toddler son into poverty by taking a non-paying job at a stock brokerage. Helping Smith nail the role was the fact that his real-life son, Jaden Smith, portrayed his on-screen son.