The phrase "an assertion against" is correct and usable in written English.
It can be used when discussing a statement or claim that opposes or contradicts something else.
Example: "The lawyer presented an assertion against the validity of the evidence provided by the prosecution."
Alternatives: "a claim opposing" or "a statement countering".
Nonetheless, when they meet they begin a passionate affair, an assertion of hope against grief.
But he was, above all, an instinctive libertarian whose whole life, as Wood writes, "was an assertion of individuality against the constraints of social privilege".
Quebec's legacy of defeat — going back, really, to the French and Indian War — bears down on all of the book's characters, and the act of writing becomes an assertion of selfhood against the backdrop of an inescapable past.
Irigaray's undertaking thus involves not merely an assertion of difference against equality, nor certainly a simple reversal; such stances take place on the basis of an already existing symbolic order and imaginary relation and are themselves what need to be interrogated.
Under normal circumstances, smashing up your iPad would be seen as a mindless, destructive act or maybe an assertion of protest against consumer society.
This was not some foolish boast of racial superiority, just an assertion of standing tall against the world.
He was widely criticized for defending Bush policies on abstinence-only education and global warming, especially in his defense against an assertion by the National Academy of Sciences that political influence was contaminating the scientific research in government agencies.
In fact, Mr. Pataki declined to respond when asked if he agreed with the declaration by the Republican senatorial candidate in 2000, Rick A. Lazio, that the upstate economy had "turned a corner," an assertion Mrs. Clinton turned against Mr. Lazio to devastating effect in the final weeks of that campaign.
However, the soul theorist's account of what is needed to make an assertion begs the question against those who believe that a healthy brain is enough for mental states.
Such projects were a protest against nature, an assertion of technological divinity.
