Yes, the United States makes frequent use of human rights as a foreign policy instrument. When it stands by while one of its allies harasses human rights activists in order to silence them, the United States weakens its criticisms of other countries for similar incidents. If it wants to promote human rights throughout the world, then it must be willing to speak up even when it is politically inconvenient.
The United States and Saudi Arabia have been allies for decades now. These countries share a close diplomatic and military relationship that affords the United States significant influence on the Kingdom. While the United States cannot oblige the Saudis to act one way or another on an issues of domestic affairs, it has an obligation as a leading democracy to pressure the Kingdom on the release of a women's rights activist. While western cultural values may or may not apply in specific instances, the United States cannot shirk its responsibility of promoting democratic rights with its allies.
We should support anyone that selflessly fights for human rights of others. She was presented the 2012 International Women of Courage award by the United States. To turn our back on someone that stands for what we believe would be disgraceful. The United States needs to stand behind her and help to free her.
Samar Badawi, a Saudi woman's rights activist, was arrested recently for the crime of "running a twitter account in her dead husbands name." Her sister, another activist, was jailed for insulting the religious establishment and sent to prison for 10 years. I believe that morally, the United States has the obligation of upholding human rights, even in other countries. Especially since in this case, the Saudi government was clearly looking for something to jail Badawi for.