The phrase "a voluntary campaign" is correct and usable in written English.
It can be used to describe a campaign that is undertaken willingly and without coercion, often for a cause or initiative.
Example: "The organization launched a voluntary campaign to raise awareness about environmental issues in the community."
Alternatives: "an optional campaign" or "a self-initiated campaign".
The city operates a voluntary campaign finance system.
New York has a voluntary campaign finance system, embraced by almost all candidates other than Mr. Bloomberg, that sharply limits spending by participating campaigns.
"The core of it has to be a voluntary campaign finance system that takes campaigns off the treadmill of private high-stakes fund-raising".
When it was over Chrysler had agreed to a voluntary campaign, announced on Tuesday, to inspect and upgrade 2.7 million Jeeps that the government had claimed were prone to catastrophic fires in rear-end collisions.
"Chrysler Group will conduct a voluntary campaign with respect to the vehicles in question that, in addition to a visual inspection of the vehicle will, if necessary, provide an upgrade to the rear structure of the vehicle to better manage crash forces in low-speed impacts," the company said.
During Christie's campaign for reelection last year, the staffers who dealt with mayors in their government jobs were enlisted in a "voluntary" campaign to try to rack up Democratic endorsements -- part of Christie's effort to buff his national image in preparation for a possible 2016 presidential run.
Public disgust led to a law establishing a voluntary public campaign financing system for state officeholders.
Nissan is conducting a voluntary service campaign to replace this part without charge.
A voluntary public campaign finance system would allow average citizen-taxpayers to buy back control over their democracy -- truly a bargain of a deal.
Solution lies with communities The government is planning to begin a voluntary disarmament campaign in Jonglei State in March, with UNMISS monitoring for human rights violations.
The governor has already waded into a feud with good government groups by rejecting the voluntary campaign contribution limits adopted by his predecessor, Eliot Spitzer, and by putting campaign finance reform on the back burner during the legislative session.
