Cindy Sheehan, the bereaved mother who became a figurehead for the US anti-war movement, is abandoning her fight after growing disenchanted with the campaign.
Cindy Sheehan's son died fighting in Baghdad in 2004
She has camped outside President Bush's ranch since 2005, demanding a meeting over the death of her son in Iraq.
But announcing the end of her campaign, she also hit out at Democrats and anti-war campaigners who put "personal egos above peace and human life".
She said she had sacrificed her health, her marriage and her finances.
In a letter on the Daily Kos website titled Good Riddance Attention Whore - a reference to the abuse she says she has suffered, Ms Sheehan said: "I am going to take whatever I have left and go home.
"I am going to go home and be a mother to my surviving children and try to regain some of what I have lost."
Cindy Sheehan became a "postergirl" for the US anti-war movement after she set up her protest camp outside the president's ranch in Crawford, Texas in August 2005.
She said she has spent all the money from the survivor's benefits paid for her son's death and everything she earned from speaking and book fees and that she owed large hospital bills.
"I have been called every despicable name that small minds can think of and have had my life threatened many times."
She said her son Casey, who died in Baghdad in April 2004, was "killed by his own country which is beholden to and run by a war machine that even controls what we think.
"Casey died for a country which cares more about who will be the next American Idol than how many people will be killed in the next few months while Democrats and Republicans play politics with human lives.
"It is so painful to me to know that I bought into this system for so many years and Casey paid the price for that allegiance. I failed my boy and that hurts the most."
Ms Sheehan criticised the US anti-war movement for often putting "personal egos" first.
"It is hard to work for peace when the very movement that is named after it has so many divisions."
She said that one-time allies among the Democratic Party had turned on her when she no longer limited her protests over the Iraq war to the Republican Party.
The US will rapidly descend into "a fascist corporate wasteland," she said, if "alternatives to this corrupt 'two' party system" are not found.
Ms Sheehan said she was resigning as the "face" of the US anti-war movement.
She said she would "never give up trying to help people in the world who are harmed by the empire of the good old US of A, but I am finished working in, or outside of this system."