The phrase "defend the idea" is correct and usable in written English.
You can use this phrase when you need to explain why you believe a particular idea is sensible and valid. For example, "I strongly defend the idea that every student should have access to a quality education."
"The mayor is appropriate to defend the idea of a grading system; I defend the idea of a grading system," Ms. Quinn said in an interview.
Some Rembrandt specialists defend the idea that for several years he commuted between Leiden and Amsterdam.
Baseball insiders cite factors like cohesion, rhythm and percentages to defend the idea of sticking with tried-and-true players.
We defend the idea that determining the difficulties web site designers encounter is necessary to better support their design activities, especially in making web sites easier to use.
Labour must defend the idea of a public realm as distinct from the Tory caricature of the over-mighty state.
"To defend the idea that women come out different on some cases, I just feel it," Judge Kaye said.
Thus far, no "traditional journalist" has been silly enough to own up to and defend the idea of belonging to an élite from which ordinary citizens are barred.
I absolutely defend the idea that to change things, that ownership of change, how you bring people together, that's what the job should be".
That in turn requires the politicians to defend the idea of Spain more effectively even as they give due recognition to their country's regional diversity.
The goal of the chapter is not just to defend the idea that humans evolved but to offer evolutionary explanations of specific human features in terms of natural selection.
However, nobody would defend the idea of 9% of projects using valuable non-human primates (NHPs) that do not result in good science.
