In contrasting explanation with understanding, it is helpful to think about past lives.  Two persons of interest are

Diocletian and Tekemthe.  My comments about them are derived from several sources:

The careers of Diocletian and Takemthe/Tecumseh, which are used to exemplify aspects of understanding and explaining international relations, are related in

Secondary sources:
R. David Edmunds,  The Shawnee Prophet.  Universisty of Negraska Press, 1983.
Bil Gilbert, God Gave Us This Country: Tekamthi and the First American Civil War. Atheneum, 1989. E99.S35 T147 1989.,

A compilation of contemporary's words about Tecumseh, drawn from many primary sources:  C. F. Klinck, ed., Tecumseh: Fact and Fiction in Early Records. Ottawa, The Tecumseh Press, 1978.

Also useful are

Web history of the Iroquois, noting Tecumseh; Encyclopedia Brittanica On-Line here.

For an earlier period , see Neta Crawford, "A Security Regime Among Democracies," International Organization 48, 3(Summer 1994), pp. 345-385.
 

Diocletian (like most Roman generals of the period) was in all probability only marginally literate, so we don't have his "memoirs" even as fiction.  Instead, see

Stephen Williams, Diocletian and the Roman Recovery. Methuem, 1985. DG313 .W54 1985.
Timothy D. Barnes, The New Empire of Diocletian and Constantine. Harvard University Press, 1982. DG313 .B354.)

James William Ermatinger, The economic reforms of Diocletian. St. Katharinen 1996.

Simon Corcoran, The Empire of the Tetrarchs : Imperial Pronouncements and Government Ad 284-324. Oxford University Press, 2000.