Letter from America: The most popular non-fiction author in the US right now is 81 years old and widely regarded as one of his country's outstanding political failures.
Jimmy Carter has himself acknowledged that he has been a better ex-president than he was a president, winning the Nobel Peace Prize in 2002 for his efforts "to find peaceful solutions to international conflicts, to advance democracy and human rights, and to promote economic and social development".
Our Endangered Values - America's Moral Crisis, which has gone straight to the top of the New York Times bestseller list, is a passionate denunciation of the religious and political fundamentalism that Mr Carter believes to have hijacked America's government and much of its religious leadership.
The former president's deep religious faith and experience of power at the highest level lend his analysis an unusual authority as he argues that the Christian right is distorting the message of Christ and the Bush administration is betraying the US's most basic political values.
Conservatives are outraged, with the online magazine Front Page describing Mr Carter as "the world's worst ex-president" and accusing him of smearing evangelical Christians and lying about his own record.
For the majority of Americans who believe their country is going in the wrong direction - 68 per cent according to a Harris poll published this week - Mr Carter's assault on fundamentalism from a Christian perspective may feel like a breath of fresh air.
For Mr Carter, fundamentalism is characterised by "rigidity, domination and exclusion", with fundamentalists drawing "clear distinctions between themselves, as true believers, and others, convinced that they are right and that anyone who contradicts them is ignorant and possibly evil".
He describes how the Southern Baptist Convention, to which his own church was once affiliated, abandoned Baptists' traditional commitment to the separation of church and state and to the autonomy of local churches and allied itself with the Republican party. The alliance of conservative Christians and neoconservative political activists poses "a threat to many of our nation's historic customs and moral commitments, both in government and in houses of worship".
Mr Carter argues that powerful lobbyists have distorted America's belief in free enterprise into the right of the richest to accumulate more and more wealth, while intensely committed hardliners impose their minority views on abortion and homosexuality.
As a Christian, Mr Carter opposes abortion and the death penalty but as president, he upheld abortion rights and the right of states to execute convicted felons. He suggests that, if Christians really want to reduce the number of abortions, they should promote sex education, access to contraceptives and better support for poor mothers.
He condemns the targeting of homosexuals by some Christians who seek a constitutional amendment to ban gay marriage while upholding the right of married couples to divorce.
"Since the punishment for adultery in the Christian era and more ancient times was death, and since Christ himself strongly condemned both adultery and divorce, a constitutional amendment with more biblical authenticity might be 'Adultery and divorce are condemned, and marriage is defined as a legal and spiritual union between a man and a woman until they are parted by death'."
With a clear majority of Americans condoning divorce and believing it is acceptable for gays and lesbians to engage in same-sex behaviour, it may be best to leave the US constitution alone, he says.
Mr Carter reserves his fiercest rhetoric for the Bush administration's foreign policy since September 11th, 2001, although he avoids direct criticism of the president, perhaps out of respect for the office. Describing the Iraq war as "unjust and unnecessary", he claims the invasion has increased the terrorist threat to America while alienating important allies.
In a lengthy discussion on the abuse of prisoners in US custody and the reduction of civil liberties in response to terrorism, he says the treatment of captives has brought discredit on the US.
"It is an embarrassing tragedy to see a departure from our nation's historic leadership as a champion of human rights, with the abandonment defended legally by top officials. Only the American people can redirect our government's legal, religious and political commitments to these ancient and unchanging moral principles," he says.
