The full interview will air on Cavuto's show Wednesday at 8 p.m. on the Fox Business Network.
The two most important issues the U.S. should keep an eye on, the George W. Bush appointee added, are Iran’s nuclear program and Iran’s relationship with Syria.
Syria’s other allies, Russia and China, have warned the U.S. in the last day that the administration must abide by international law, and get approval from the United Nations Security Council. Russia said, otherwise, an attack would have "catastrophic consequences."
Asked if Rumsfeld thinks Russia and China would act on their threats, he said, “Well, it's hard to know. I mean there's no question that each of those two countries, the People's Republic of China and Russia, have leaders that are fundamentally opposed to our values and our interests.”
Rumsfeld also said that Secretary of State John KerryJohn KerryThe challenge: Reaching 350 million youth worldwide Obama’s Iran playbook gives hope to Darfur A case for the Yarmuth-Price resolution MORE “has been dealt a pretty bad hand” as a result of President Obama’s and former Secretary of State Hillary ClintonHillary Rodham ClintonDem senator compares Obama's moves in Syria to Putin's in Ukraine Cruz-Fiorina ticket releases first television ad Ralph Nader: 'Why should Bernie Sanders drop out?' MORE’s decisions over the last four years.
Rumsfeld stepped down from his post as Defense secretary in 2006.