"firmly argued" is a correct and usable phrase in written English.
It can be used whenever you need to describe an argument or opinion that is strongly and confidently expressed. For example, "He firmly argued that the policy should be changed."
It firmly argues that building single-family homes rather than tower blocks creates a sense of individual pride in their residents and avoids public spaces becoming neglected and mired in criminal behaviour.
Hence, it is apparent that recent studies firmly argue the effect of natural and anthropogenic contamination sources on groundwater composition, especially in coastal aquifer, and also imply the necessity of groundwater contamination studies in coastal aquifer.
Depending also on the length and scope of the conversation you may have to firmly argue or question more than once.
And the scientific community firmly resisted, arguing that the best defenses came with the open flow of information.
Labor and the Greens are firmly opposed, arguing the measures would expose students to large fee increases, which would be exacerbated by the impact of compound interest on student loans.
At the time he argued firmly that the shroud, which bears a Christlike image, was a clever forgery.
Just as I have argued firmly for compassion and fairness in life, I believe that terminally ill people should be treated with the same compassion and fairness when it comes to their deaths.
"Just as I have argued firmly for compassion and fairness in life, I believe that terminally ill people should be treated with the same compassion and fairness when it comes to their deaths," he added.
Throughout his life John firmly but courteously argued not only for objectivity and good manners within science, but also for the superiority of rationality over hunch or prejudice in its social discourse and practical applications.
