NEXT TUESDAY in Tallahassee, the Florida Senate will have a chance to set its state -- and the nation -- on a path away from the dangers of a federal constitutional convention. The Senate will vote on a resolution offered by state Sen. Edgar Dunn (D) of Daytona Beach, which among other things would withdraw the petition the Florida legislature sent to Congress in 1976 calling for a federal constitutional convention to pass an amendment requiring a balanced federal budget. Half the state senators are cosponsoring Mr. Dunn's resolution, and there's a good chance it will pass both houses. Then, in Mr. Dunn's view, Florida can no longer be counted as one of the states calling for a constitutional convention.

This matter is anything but trivial. The Constitution says that Congress must convene a federal constitutional convention when 34 legislatures call for one, and in the past several years 32 legislatures have done so (though not in identical language). Backers of a balanced budget amendment hope they can get the two additional resolutions some time this spring. But if Florida rescinds its call for a convention and other states follow suit, the movement for a convention would probably fizzle. There's dispute over whether a state can rescind, or whether, having once called for a constitutional convention, it must forever be entered on the roll of states favoring one, even if it has changed its mind. But it seems reasonable to say that a state that voted for a constitutional convention in 1976 but voted against one in 1985 can't be counted as favoring one in 1986 or 1987. And the example of a state's explicitly renouncing the convention and the amendment will surely undermine the drive for both -- a salutary development, in our view.

It's instructive to see what has moved legislators in as practical and conservative-minded a state as Florida to turn their backs on the amendment. Some reportedly don't want to see spending cut as much as would be required to balance the federal budget. But more are motivated by an uncertainty about how a constitutional convention would operate. What are the rules? How are members elected? Can it be limited to one subject? Are we, as Mr. Dunn says, "playing Russian roulette with the Constitution"?

Finally, it has dawned on more than one Florida legislator that an amendment is a confoundedly inefficient way to balance the budget. The first provision in Mr. Dunn's resolution requests Congress to take immediate steps to balance the budget and cut the deficits. President Reagan talks as if the only thing preventing a balanced budget were the opponents of the balanced budget amendment. But as people in Tallahassee and Daytona Beach know, the president and Congress already have full constitutional authority to balance the budget any time they want to. A constitutional convention would divert attention and energy away from the task that Mr. Reagan seems bent on avoiding: cutting his budget deficits down to reasonable and bearable size.