REUTERS/Don Himsel/Pool
Donald Trump.
The Republican front-runner noted that CNN reportedly hiked its advertising rates 40 times their normal rates for the September 16 debate, which it is hosting.
"While I refuse to brag, and you know very well, this tremendous increase in viewer interest is due 100% to 'Donald J. Trump,'" Trump wrote to Zucker.
Trump's campaign forwarded the letter to reporters and posted it on social media.
Fox News hosted the first official, prime-time debate and saw viewership soar to a reported record of 24 million viewers. Trump suggested that this was expected due to his star power.
"As you are aware, for the first debate, FOX unexpectedly (but not to those who know), had one of the largest audiences in the history of cable television, 24 million people plus, and word is that your audience will be even larger," he wrote.
Trump then informed CNN that the network should view its debate as "a public service and not accept the massive profits that this airing will generate."
"I believe that all profits from this broadcast should go to various VETERANS groups, a list of which I will send to you in the near future," he wrote. "The veterans of our country, our finest people, have been treated horribly by our government and its 'all talk and no action' politicians."
"In fact, some would say they are treated like third class citizens - even worse, in many cases, than illegal immigrants. It is about time that someone comes to their aid. Let's start now!" he added. "This large contribution of many millions of dollars would be a truly wonderful thing for CNN to do."
The billionaire Republican concluded the letter by noting his own past generosity to some veterans' causes.
Business Insider reached out to CNN for comment and will update if we hear back.