The phrase "principal advocate" is correct and usable in written English.
You can use it when you want to refer to someone who speaks or acts on behalf of something or someone else. For example, "The principal advocate of the bill argued that it would have positive effects on the economy."
Behaviourism's principal advocate, John B. Watson, was interested primarily in stimulus response relations.
The principal advocate for the accused was Wilfred E. Cooper, the principal defense attorney was David Blomberg.
Mr. Powell is also known as the administration's principal advocate for seeking United Nations support before military force is used.
The NRA says "he was a principal advocate for the establishment of the NRA's Political Action Committee".
During the Second World War, Madame Rotival was the principal advocate and fundraiser in North America for the Free French.
"The president of the United States is supposed to be the principal advocate for American policy and interests in the world," he said.
Their principal advocated on their behalf, and in August, Ms. Mata's son was promoted.
The term science fiction was popularized, if not invented, in the 1920s by one of the genre's principal advocates, the American publisher Hugo Gernsback.
One of its principal advocates was the Oxford ecologist Charles Elton, whose book "The Ecology of Invasions by Animals and Plants," argued that simplifying landscapes with weedkillers, or planting single crop species over large areas made a recipe for disaster.
One gender trigger that may favor women over men is playing the role of agent (advocating for others) as opposed to playing the role of principal (advocating for themselves).
Spread by the wind, like blowing pollen, they could be designed to replicate swiftly and reduce life on earth to dust in a matter of days, according to Eric Drexler, one of the nation's principal advocates for nanotechnology.
