An interesting ambiguity came up for discussion today. The verbal phrase to fight with x usually means, in the vast number of examples, that x is an opponent in the fight. However, in some explicit contexts, such as when explicitly opposed with to fight against, to fight with can mean precisely the opposite, that x is your comrade in arms.
Examples (from Google books) of fight with or against:
Should they fight with or against their masters?
A People and a Nation, Volume I: A History of the United States: … – Page 148
Even if he knew whether to fight with or against Dr. Georges-Scales, he couldn't.
Seraph of Sorrow – Page 187
Now the naked question was, whether Virginia should fight with or against her sisters of the Gulf States.
A life of Gen. Robert E. Lee – Page 25
Yeah, an interesting ambiguity for sure. My take is that it's one of those phrases that depends more on whether it's written and formal, or conversational and informal. For example, I often hear or say:
I had fight with my wife.
I had a fight with my best friend.
I had a fight with my son/daughter/mother/father.
The examples you quote about "fighting against" all have to do with institutional conflicts, as in a declared war or revolution, and so the more formal "fight against" just sounds more correct to my ears.
The ambiguity was noted by comedians at least as far back as vaudeville:
"My great-grandfather fought with General Sherman, my grandfather fought with Pershing, and my father fought with MacArthur."
"Gee, your family couldn't get along with anyone!"
I believe Abbott & Costello did that routine. Probably many others comedic pairs too. Had forgotten about that "2-liner" till Ron mentioned it. Funny!
Was thinking some more about the fight with vs. fight against usage patterns, and keep coming back to my hypothesis regarding informal vs. formal conflicts. The "opponent" doesn't even need to be a person or institution or nation. Here's some more expressions I've heard or used:
I'm fighting with the phone company over that last bill.
I've been fighting with the alarm system settings on my car for the last two weeks.
Been trying to program my DVR to record that series, but I'm still fighting with that damn menu system.
Curiously, when the "opponent" is a disease they (at least in advertising) seem to prefer the more formal:
Helps you in your fight against hair loss.
The fight against obesity can be won using our new diet program.
We'll help you every way we can in your fight against cancer/diabetes/MS, etc.
I suspect that choice is made by ad copy writers because it makes them sound more "serious." It also anthropomorphizes the disease, giving it a "face" and identity at which to target the treatment.
I gather (mostly from reading old books and authors) that children a hundred years ago used to be taught this difference carefully—which implies that even then they tended to use "with" carelessly when they really meant "against". That struggle is almost lost nowadays, except that it's still necessary to the language and so crops up occasionally in people's awareness.
Then, too, some fights against are also fights with. If you're a boxer, surely your fight against Mohammed Ali (dating myself, here) is also in a sense a fight with him? And, too, some people like to fight, so many fights you and your best friend get into could be fights with him....depending on just how annoyed you are, and for how long afterward.