Asked at the Council of Foreign Relations if THAAD systems would be placed on the peninsula, Carter was direct, saying "Oh, it's gonna happen."
"It's a necessary thing. It's between us and the South Korea, it about protecting our own forces on the Korean peninsula and about protecting South Korea. It has nothing to do with the Chinese," Carter said. "We need to defend our own people, we need to defend our own allies."
Chinese officials have publicly attempted to dissuade the US and South Korea from coming to an agreement on THAAD, leading Adm. Harry Harris, head of US Pacific Command, to hit back in a February briefing.
"China's interference in a decision that's to be made between alliance partners — the Republic of Korea and the United States — their inference in that process is preposterous, especially when you consider that THAAD is not a threat to China," Harris said.
Like Harris, Carter Friday cast the THAAD issue as one between the US and South Korea, but said he was "quite encouraged" by strengthening bilateral ties between Seoul and Beijing.
He added he wished "the Chinese would work with us, or work bilaterally with North Korea more effectively bilaterally, although it's easy to say that… at heading off the missile challenge in the first place."
Aaron Mehta was deputy editor and senior Pentagon correspondent for Defense News, covering policy, strategy and acquisition at the highest levels of the Defense Department and its international partners.