It is not in the American interest to have conditions of extreme tension, even less of war, between the Soviet Union and China...
What does "even less of war" mean?
It is not in America's interest to have a condition of extreme tension between the Soviet Union and China.
It is even less in America's interest to have a condition of war between the two nations.
It is not a very clearly-written sentence.
It is not in the American interest to have conditions of extreme tension, even less, of war, between the Soviet Union and China...
I think you need a comma after 'less', to keep the original sentence.
Soothing Dave's version reads so much better.
not a teacher