In addition to the many other problems  with the “conservative internationalism” Nau describes in his book  of the same name, he has made an exceedingly odd selection of presidents that he claims for this view. Nau identifies Jefferson, Polk, Truman, and Reagan as conservative internationalists, and his main reason  for doing so is this:
These four American presidents did more to expand freedom abroad through the assertive use of military force than any others.
If the foreign policy records of the four presidents seem to have little in common, that is because they represent very different foreign policy traditions and are being thrown together in a bid to offer something to almost everyone. Jefferson and Polk could arguably be identified as part of the same tradition, and both were undoubtedly territorial expansionists, but it makes no sense to see them as having much in common with internationalists of a later century. When Jefferson pursued expansionist policies, he did so without relying on military force, and when he resorted to the use of force he was not doing so for expansionist reasons, much less to “expand freedom abroad.” Polk pursued territorial expansion by force, but was not particularly concerned with “expanding freedom abroad.” The inclusion of Truman is strange for a number of reasons, not least of which is the fact that Truman is obviously a liberal internationalist in the same tradition as his predecessor. It is questionable how much Truman did in office that resulted in the expansion of freedom abroad. Containment policy arguably helped to defend free or semi-free societies where they existed, but by design it was not an expansionist doctrine.
That leaves Reagan, who is the only one of the four that deserves the label conservative internationalist, and even he doesn’t really fit Nau’s definition. Nau’s conservative internationalism is designed to use a misreading of Reagan’s foreign policy as the essence of an entire tradition that supposedly dates back to the earliest years of the republic, but it should be clear that these four presidents aren’t part of the same tradition and some of them don’t even qualify as internationalists.