First, neither is a compete sentence. There is no main verb. In your second, the author is no longer mentioned, and "do" should be "does".
Student or Learner
"Imposing a pattern which, so the author contends, the facts do not warrant."
This sentence has been taken from the following link:
Can the sentence take the following form without changing its meaning?
"Imposing a pattern which do not warrant the facts."
Thanks to all.
Please note that a better title would have been Imposing a pattern.
Extract from the Posting Guidelines:
'Thread titles should include all or part of the word/phrase being discussed.'
No! Warrant doesn't work that way.
The facts do not warrant X.
X is not warranted by the facts.
To say "the facts do not warrant X "and "X does not warrant the facts" are equivalent sentences is wrong, even if there is subject verb agreement.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.