“I support this plan 100 percent,” Mr. Wexler said before introducing Mr. Crist. “This governor means what he says, and he’s coming to Tallahassee and he’s spreading the message throughout Florida that this isn’t about Republican or Democrat, it’s not about this ideology or that; it’s about unifying people and doing what’s right for the people of Florida.”

The 15 Florida counties that have adopted touch-screen voting in recent years, including Miami-Dade, Broward, Palm Beach and Hillsborough, would move to optical-scan voting under the proposal before the presidential election of 2008. The plan would give them the option, however, of using touch-screen machines during the state’s two-week early voting period that precedes Election Day, if the machines are modified to provide a paper trail. Those counties represent 54 percent of the state’s registered voters. Broward County alone has bought about 6,000 touch-screen machines in recent years, and Palm Beach County has about 4,500.

Mr. Crist said county election supervisors would explore how to make optical-scan voting easier for blind people and for those who speak foreign languages. In some cases, they have been able to vote without assistance on the touch-screen machines.

Asked how he felt about discarding tens of millions of dollars worth of touch-screen machines just years after they were acquired, Mr. Crist said, “The price of freedom is not cheap. The importance of a democratic system of voting that we can trust, that we can have confidence in, is incredibly important.”

Election experts estimate that paperless electronic machines were used by about 30 percent of voters nationwide in 2006. But their reliability has increasingly come under scrutiny, as has the difficulty of doing recounts without a paper trail. Federal technology experts concluded late last year that paperless touch-screen machines could not be secured from tampering.

Some states had bought early versions of the paperless machines before the 2000 recount, and one of them, New Mexico, switched last year to optical scanners. But most of the machines in other states were purchased with federal money provided under a 2002 law that required states to upgrade from old punch-card and lever systems.

New York is planning to buy either screens with printers or optical scanners, New Jersey is adding paper trails to its touch screens and Connecticut is buying the optical scanners. A recent survey by Election Data Services, a Washington consulting firm, estimated that 36 percent of the nation’s counties have bought electronic machines, including some with printers attached, while 56 percent have the optical scan systems.