WASHINGTON | Thu Mar 1, 2012 11:35am EST

WASHINGTON (Reuters) – Conservative activist Andrew Breitbart, an influential voice in U.S. Republican politics known for his attacks on liberals and Democrats, died unexpectedly of natural causes in Los Angeles early on Thursday, his family said. He was 43.

The brash and outspoken blogger and commentator, who published politically inspired photos and undercover videos, was the center of several major news websites, including http://www.Breitbart.tv, http://www.breitbart.com and http://www.biggovernment.com.

Breitbart was walking last night near his Los Angeles home when he collapsed, said his father-in-law, actor Orson Bean.

“He collapsed on the sidewalks and the paramedics were there very quickly and they couldn’t revive him,” Bean told Reuters.

Bean, 83, said that he was told by his daughter at around 1:30 a.m. that Breitbart had died. He said that he did not know if Breitbart had any heart troubles. “We were very close so I think if he had I would have known,” Bean said.

“We have lost a husband, a father, a son, a brother, a dear friend, a patriot and a happy warrior. Andrew lived boldly, so that we more timid souls would dare to live freely and fully, and fight for the fragile liberty he showed us how to love,” a memorial page on his websites said. The page said Breitbart “passed away unexpectedly from natural causes.”

Breitbart was notorious for his fiery opinions. The last posts from his Twitter feed appear to have come just moments before midnight, with one calling a user a “putz” and another replying “Apologize for WHAT?” to another user.

His work played a role in a number of prominent news stories in recent years, including undercover videos of the community group ACORN and the texting scandal of former Democratic U.S. Representative Anthony Weiner of New York.

“Andrew’s death is a shock & huge loss. His courage should be an example to us all,” Republican presidential candidate Rick Santorum said via Twitter.

Former Republic presidential candidate Herman Cain, in a tweet, wrote: “I admired @AndrewBreitbart’s fighting spirit. Thoughts & Prayers to his family. He was my friend & I will miss him #RIP.”

Even ideological opponents praised Breitbart.

“Andrew Breitbart was a conservative political combatant who was unafraid of his critics,” tweeted Donna Brazile, Democratic Party strategist and former presidential campaign manager for Al Gore. “We battled on and off air, but he was a genius.”

In his book “Righteous Indignation,” Breitbart wrote: “I love my job. I love fighting for what I believe in. I love having fun while doing it. I love reporting stories that the Complex refuses to report. I love fighting back, I love finding allies, and-famously-I enjoy making enemies,” according to his website.

“At the end of the day, I can look at myself in the mirror, and I sleep very well at night,” Breitbart wrote in the book.

(Reporting by Susan Heavey and Alex Dobuzinskis; Editing by Anthony Boadle)

vERY SAD NEWS INDEED for one so young that did so much for us all,Rip Andrew you did great good for the cause of conservatism in the US, and getting the truth out to the masses of just what Big Government is and what really is happening in the US now,  this came way to early for youYou will be greatly missed but never forgotten sir ..God Bless ,Rip great warrior and Patriot.

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