• If the initiative is approved in Massachusetts, taxpayers would be asked to check off a special box on their income tax returns for money to go to the campaigns -- which opponents claim will cost taxpayers $56 million every four years.

• The Arizona initiative would raise money by increasing lobbyists' fees from $25 to $100, impose a 20 percent surcharge on civil and criminal fines and incorporate a tax-form check-off.

• Maine passed the first full public-financed campaign system in 1996, and the Vermont Legislature passed a similar measure last year -- but neither of the new laws takes effect until the year 2000 elections.

• About 16 percent of Maine's taxpayers chose to check a box on their form this year which directed $3 to go to the state's campaign fund.

In 1976, the U.S. Supreme Court ruled that campaign spending is a form of free expression protected by the First Amendment. The public financing initiatives attempt to work around that by keeping candidates' participation voluntary.

If, after an initial spurt of small-donation gathering to qualify, candidates renounce all fund-raising, they will get enough public money for a moderate campaign budget, supporters say.

Observers expect that Missouri, Washington and Oregon will be the next states to take up public campaign financing. But the constitutionality of such plans will, without doubt, be tested.