A top aide to President Barack Obama insisted Wednesday that human rights were at the core of US foreign policy but admitted "painful" trade-offs are sometimes made in the name of national security. National Security Adviser Susan Rice argued that it was not easy to be consistent when promoting human rights in a world of swirling geopolitics and authoritarian governments, and said the issue was not the only interest dictating U.S. policy. "We sometimes face painful dilemmas when the immediate need to defend our national security clashes with our fundamental commitment to democracy and human rights," Rice said in prepared remarks for a speech at a Human Rights First summit. "Let's be honest: at times, as a result, we do business with governments that do not respect the rights we hold most dear," she said. "We make tough choices. When rights are violated, we continue to advocate for their protection." "But we cannot, and I will not pretend that some short-term tradeoffs don't exist," she added. Rice argued that for reasons of history and its own values, the United States should always put human rights and democracy promotion at the center of its foreign policy. She said Obama required his foreign policy lieutenants to stand up for the rights of women, lesbians and gays, ethnic minorities, and for freedom or worship, open government and free assembly and a free press. But she also warned that a president's ultimate duty lay in protecting the security of his country and its people, hinting that sometimes this led U.S. leaders to partner with uncomfortable bedfellows. "Advancing human rights is not, and has never been, our only interest," Rice said. "Every U.S. president has a sworn duty to protect the lives and fortunes of the American people against immediate threats." "That is President Obama's first responsibility, and mine," she added. "We must defend the United States, our citizens and our allies with every tool at our disposal, including, when necessary, with our military might." Some critics of the administration have accused Obama of soft-pedaling human rights to avoid prejudicing U.S. relations with key powers like China and Russia. Obama has also been charged with turning a blind eye to the gross infringements on human rights in Syria's civil war as he tries to ensure Washington is not embroiled in another Middle Eastern conflict. Many human rights activists have also questioned the morality of the U.S. drone war against terror suspects in lawless places like Pakistani border areas and Yemen -- which critics say has killed scores of civilians caught in the crossfire.