and why ?

I'm positing that we are discussing the manual cited by Slap, which would be USMC MCDP 1-1, Strategy. Three relevant (and seemingly to me, material) quotes from that publication, dealing with "Ends" and "Means", are these ....

p.40 pdf:

Strategy, broadly defined, is the process of interrelating ends and means. When we apply this process to a particular set of ends and means, the product — that is, the strategy — is a specific way of using specified means to achieve distinct ends. Strategy is thus both a process and a product. Any discussion of ends and means in war must begin with two basic points. First, as we have observed, war is an expression of politics. The ends or goals of any party waging war — even though those goals may be social, economic, religious, or ideological in nature — are by definition political goals. Second, wars are fought by political entities that have unique characteristics and often very dissimilar goals and resources. In order to understand any conflict, we must appreciate the ways in which the means and ends of the participants may vary.
and p.46-47 pdf:

MEANS IN NATIONAL STRATEGY

In the purest sense, the means in war is combat — physically attacking the enemy or defending against his attacks upon us. However, war is not limited to purely military means. In fact, military means are only one element used to implement a national strategy. The relative importance placed on the military element of the national strategy varies greatly depending on the nature and the particular circumstances of the struggle. All of the instruments of power — diplomatic, economic, military, and informational — must be brought to bear and exploited to the fullest in war.
and p.54 pdf

ADAPTING ENDS TO MEANS, AND VICE VERSA

When discussing strategy in the abstract, we often treat means and ends as fixed. In practice, however, we frequently adjust both. The occurrences of war — successes and failures, lessons learned, new ideas, the entry of new combatants — may cause us to shift both our means and our goals. As our resources increase, as we gain confidence in our abilities, and as we find
our enemy more vulnerable than we had imagined, we tend to expand our goals.
Where are the grave[*] errors and heresies in the above ? Please enlighten, so I can get back to my hamster joust.

[*] One can quibble about whether there are three DIE (diplomatic, informational, economic) elements or more - all of these (3 or more) non-military elements being part of the "politiical struggle" in my eyes.

Regards

Mike