Q. I know that there’s a rule that says if two adjectives can be joined by the word and without affecting the meaning, then you should separate the two adjectives with a comma. But sometimes a hyphen seems like the better choice. For example: “a historical-philosophical context” or “military-political involvement.” Do you agree?
A. The hyphens in historical-philosophical and military-political imply a mix of factors that’s more complex than what and would suggest—more of an intersection than a pair of attributes. If that’s what you intend, keep the hyphens rather than replacing them with commas.
These adjectives are equivalent to a term like socioeconomic, in which the word social in social-economic has become the combining form socio- and joins with economic to become one word (some of these terms retain their hyphens; see CMOS 7.96, sec. 2, under “combining forms”).
In fact, the similar term historicophilosophical is entered in Wiktionary and makes an appearance as an example under historico- in Merriam-Webster, so you could consider using that form instead of historical-philosophical (though you could retain the hyphen in this unwieldy compound for the sake of legibility: historico-philosophical).
There’s no established combining form for military, but military-political works well. Or you could try politico-military, as entered in Wiktionary.