He recalled that China has already been in talks with Moscow to buy Russian RD-180 rocket engines, "the very ones America was on course to buy until sanctions kicked in." Earlier this year, the US Congress passed a legislation barring the use of RD-180 engines in future US military missions.
Johnson, who is also a former F-15 fighter pilot, warned of serious consequences if congressional action fails to "quickly reverse China's access to Russian heavy-lift engines."
"We may be seeing those Russia rocket engines again, but from a very different perspective as they provide a robust ballistic missile system for a nation not so friendly to US national security interests," Johnson said.
He referred to China testing its new intercontinental ballistic missile in August 2015, which Johnson described as an important technological breakthrough for the country. According to him, this is a "uniquely dangerous" step.
"The proliferation of multiple Chinese warheads, or heavy-lift rockets carrying nuclear-tipped 'multiple independently-targetable reentry vehicles,' could put us on the fast-track to the past," Johnson warned.
He called on Congress to take urgent measures in order "to keep our cities and countryside safe."
"Congress can – and arguably must now – carefully review the list of sanctions we have imposed on Russia. This is one that should be stricken from the list, for our sake, not theirs – even if only for strategic security purposes," Johnson said.
"These Russian engines, which China may now be seeking to buy, empower our national security twice over – they help us keep eyes in the sky and they prevent others from using them for hostile purposes," Johnson pointed out.
He urged the continuation of cooperation related to Russian heavy lift rocket engines – "just as we have not sanctioned Russian transport of Americans to the space station."