TALLAHASSEE — Gov. Rick Scott is quietly working to kill legislation that would allow people in Florida to begin online voter registration in 2017, using arguments that local elections officials call "inaccurate" and "perplexing."

The Scott administration's backstage opposition claims that online voter registration has "risks and challenges," a position that has created new rifts between the governor and county elections supervisors. It also has led to speculation in the Capitol that the Republican governor may be resistant to expanding the pool of Florida voters as he considers a possible U.S. Senate bid in 2018.

It's not the first time the governor has clashed with elections officials and others over voting laws.

In 2011, Scott signed a controversial law that reduced early-voting days that critics said was designed to disenfranchise voters and discourage turnout. The 2013 Legislature repealed many of the bill's provisions.

Scott also alienated elections supervisors in his first term when he proposed publicly grading them on their job performances, and supervisors later rejected the state's flawed program to purge voter rolls of suspected noncitizens.

In February, Scott dropped an appeal of a federal court ruling that said the state illegally tried to purge the rolls too close to the 2012 presidential election. In announcing that decision, Scott said: "Our goal continues to be 100 percent participation by eligible voters and zero percent fraud."

Currently, Florida requires new voters to print, sign, date and mail or deliver a voter registration form. Twenty states, including Georgia, South Carolina and Louisiana, now allow people the option of an online voter registration application and four others, including West Virginia, are implementing it.

A bill in the Legislature by Sen. Jeff Clemens, D-Lake Worth, has broad bipartisan support and the backing of all 67 Florida county election supervisors, a majority of whom are Republicans. The bill (SB 228) allowing the option of online registration cruised through a Senate committee Thursday on a unanimous vote with endorsements from AARP, Disability Rights of Florida and the League of Women Voters.

"It's simply an electronic voter application system," Clemens said. "In 24 other states, it's been shown to save money, be more efficient and actually be more secure than the system we have right now."

No one from Scott's administration has publicly opposed the bill.

But an analysis by the staff of the state Division of Elections calls it a "mandate (that) presents potential risks and challenges" at a time when statewide databases for voter registration and driver licenses are about to undergo extensive upgrades. Florida uses driver license data to verify voters' identities.

"Malicious cyber-attacks and non-malicious malfunctions could potentially wreak havoc on an online voter registration system," the report says, and online registrations "could potentially increase the chances of votes being cast by someone other than the people actually registered to vote."

"We feel that further analysis and review is needed of states who have implemented these procedures before the Department would recommend Florida moves forward with a similar system," Secretary of State Ken Detzner said in a statement late Thursday.

But two elections supervisors said Thursday that the concerns raised in the bill analysis are invalid. Escambia County's David Stafford and Pasco's Brian Corley, both Republicans, said the risk of voter fraud is reduced with online voter registration because it diminishes the pairs of hands processing paperwork.

"Their analysis is inaccurate at best," Corley said. "I'm a little perplexed at their erroneous facts."

Corley said Detzner, the state's top elections official, has repeatedly endorsed online voter registration, but has asked for more time to implement it, and legislators have addressed his concerns.

Clemens' original bill called for online voter registration to be in place by next year — before the 2016 presidential election — but senators agreed to delay implementation until Oct. 1, 2017.

"This sets out a pretty logical timetable, getting us past a presidential election," Stafford said. "It gives ample opportunity to address any concerns that the division has. We have the benefit that 20 other states have done it."

Both the Department of State and the Department of Highway Safety and Motor Vehicles are overhauling their mainframe computer systems. Highway safety officials said Thursday that depending on timetables and funding, they hope to make significant progress on their upgrades by 2017.

A year ago, as a similar online voter registration bill stalled in the Legislature, the agency estimated it would take 270 hours of personnel time and $20,000 to make changes needed for an online registration system.

Elections supervisors, who stand for office every four years, said they would never support an idea with the potential to increase the risk of voter fraud.

In a position paper, they called online voter registration "convenient yet secure," and said: "Data has clearly shown that registering to vote online is not a partisan issue."

They also noted that a state that allows online registration is Louisiana, where Scott's chief of staff, Melissa Sellers, worked before coming to Florida.

Florida is the nation's most important swing state in presidential elections, with 29 electoral votes. The state has 12 million voters spread across 10 TV markets, but voter turnout in midterm elections is often poor, in part because Florida ranks below most states in the percentage of adults who are registered to vote.

The House sponsor of online voter registration is Republican Rep. Kathleen Passidomo of Fort Myers. With the 2015 legislative session more than half over, her bill (HB 1161) is stalled in a House subcommittee chaired by Rep. Michael Bileca, a Miami Republican.

A committee member, Rep. Blaise Ingoglia, R-Spring Hill, chairman of the Republican Party of Florida, has voiced "security concerns" about online voter registration.

Contact Steve Bousquet at bousquet@tampabay.com. Follow @stevebousquet.