Florida Governor Rick Scott vowed on Wednesday to continue a disputed effort to purge ineligible immigrant voters from the rolls, defying a federal order to halt the process.

In a letter to the U.S. Department of Justice's top civil rights lawyer, Scott rejected the Obama administration's contention that the undertaking runs afoul of the Voting Rights Act. A provision of that law mandates that certain counties with a history of discrimination -- some of them located in Florida -- get approval from the federal government before changing voting rules.

The Justice Department told Florida last week to suspend the voter purge until it could review the process. But Florida Secretary of State Ken Detzner wrote in his letter that Florida would press on, maintaining that the effort to cleanse the rolls of noncitizens extends due process to any Florida resident flagged as ineligible.

The Department of State [of Florida] respectfully disagrees with DOJ's position, Detzner wrote. The actions taken by Florida to identify and remove noncitizens from its voter rolls ensure that the right to vote of citizens is protected and is not diluted by the votes of ineligible persons.

While Florida officials have defended the process as an effort to prevent voter fraud, a preliminary list of disqualified voters contained many people who were in fact U.S. citizens. County supervisors have voiced concerns about expanding the effort -- Florida officials say they have compiled a yet-to-be-released list of more than 180,000 noncitizens on the rolls -- and the state's Democratic congressional caucus has urged Scott to defer the examination, citing fears of disenfranchisement.

Scott's letter to the Obama administration defended the process by which Floridians would be excised from the voter rolls. People identified as ineligible would be sent a letter and given 30 days to respond or challenge the letter by requesting a hearing; if the letter requesting proof of citizenship is returned as undeliverable, a notice would be published in the newspaper.

But critics say the process unjustly shifts the burden of proof to potential voters, rather than putting the onus on election monitors. The fear is that U.S. citizens will show up on election day, unaware that their valid registration is in dispute, and be unable to vote.

Florida has an uneven history when it comes to conducting elections. After President George W. Bush won the state -- and the presidency -- by the slimmest of margins in 2000, evidence surfaced that an effort to strike ineligible felons from the rolls led to many legal voters being turned away. County supervisors scarred by the experience are worried about a repeat.

The Scott administration has repeatedly drawn fire over the state's voting rules. The Department of Justice is examining a set of 2011 election laws that impose new restrictions on voter registration and limit early voting days. A federal judge recently ruled that the law tightening voter registration requirements was unconstitutional, validating groups who said the law would suppress voter turnout.