The phrase "a persistent voice for" is correct and usable in written English.
It can be used to describe someone or something that consistently advocates for a particular cause or issue.
Example: "She has been a persistent voice for environmental protection in our community."
Alternatives: "an unwavering advocate for" or "a steadfast supporter of".
He was the strongest advocate for dispatching warships early as a sign of American resolve, and his was a persistent voice for putting American troops on the ground.
Although Mr. Abbas wrote a despicable Holocaust-denying dissertation years ago, he has been a persistent voice for reconciliation and the most important Palestinian to denounce the current intifada.
Darwish, who wrote in a Palestinian newspaper after September 11 that "Nothing justifies terrorism," has clearly opposed attacks on civilians and been a persistent voice for Israeli-Palestinian coexistence.
Mr. Gray, who served in the House from 1979 to 1991, was a persistent voice for equal rights, education and services for the poor, in the United States and abroad.
She was an outspoken critic of reckless lending in the banking system prior to the 2008 meltdown and has been a persistent voice for financial reform in the years since.
But there has been a persistent voice of resistance from the insurance industry, ordinarily a strong ally of the Republican Party.
Ms. Stephenson has been a persistent voice in Stamford for the better part of 15 years.
Controversial advisor Sidney Blumenthal is a persistent voice in the emails, reporting to Clinton on international affairs, particularly relations with Britain.
But I heard a persistent voice that I couldn't ignore, and I jumped because I believed it would ultimately make me a better person, husband, and father.
"It is time for American Jews to demand that Obama instruct Israel to obey international law". Well-known actress and comedian, Roseanne Barr, has been a consistent and persistent voice for decades against some of the acts committed by the state of Israel.
"Everything in that original working paper was marginal change to the existing regulatory structure," said Jeff Connaughton, then an aide to Senator Ted Kaufman, a Delaware Democrat who became one of the most persistent voices for making more fundamental changes.
