It’s hard to think of a more important contemporary standard-bearer of American fusionist conservatism — small-government domestic policy coupled with a muscular and liberty-advancing presence abroad — than Dr. Charles Krauthammer.
To check my memory I looked up “Fusionism” in the index of George H. Nash’s The Conservative Intellectual Movement in America Since 1945. Chapter Six, “Fission and Fusion: The Quest for Philosophical Order” has the key passages, pp. 174-185 in my 1976 edition.
There is nary a word about “a muscular and liberty-advancing presence abroad.” The essence of fusionism is what I remembered it to be, as above.
Alas, the Communist threat is no longer with us. Nor do we face any comparable threat, unless you think a rabble of delusional goat-herds with box-cutters is an existential threat to the republic. (My opinion: no.)
The “liberty-advancing” thing might be worthwhile, if we knew how to do it, and could afford it. As I read the evidence, we don’t, and can’t. In any case it was no component of 1960s Fusionism, except in the (rightly) fearful and (mostly) defensive sense I just noted.