Melissa at Shakesville provides a draft letter and contact information for the State Department, asking that they take swift action to condemn the law.
The new final draft of the legislation also grants guardianship of children exclusively to their fathers and grandfathers, and requires women to get permission from their husbands to work.
"It also effectively allows a rapist to avoid prosecution by paying 'blood money' to a girl who was injured when he raped her," the US charity Human Rights Watch said.
In early April, Barack Obama and Gordon Brown joined an international chorus of condemnation when the Guardian revealed that the earlier version of the law legalised rape within marriage, according to the UN.
Although Karzai appeared to back down, activists say the revised version of the law still contains repressive measures and contradicts the Afghan constitution and international treaties signed by the country.
Islamic law experts and human rights activists say that although the language of the original law has been changed, many of the provisions that alarmed women's rights groups remain, including this one: "Tamkeen is the readiness of the wife to submit to her husband's reasonable sexual enjoyment, and her prohibition from going out of the house, except in extreme circumstances, without her husband's permission. If any of the above provisions are not followed by the wife she is considered disobedient."
Dear Secretary Clinton: I have recently become aware of the new law in Afghanistan which permits Shia men to deny their wives sustenance if they refuse submit sexually, denies mothers legal guardianship of their children, allows rapists to pay off their victims, and in other ways severely diminishes the lives of Afghan women. As I am aware of and resoundingly support your emphasis on the rights of women worldwide, I am hopeful that there will be a swift response to this appalling legislation, and I strongly encourage you to take a bold stance on behalf of the women of Afghanistan.