TALLAHASSEE — In a blow to the backers of a ballot measure passed by state voters in November, the Florida Senate will consider a more restrictive version of a bill addressing the rollout of voting rights to felons, two top Senate Republicans said Friday.

Senate President Bill Galvano, R-Bradenton, said that the upper chamber is scheduled Monday to consider a House bill that would prevent felons from voting until they’ve paid off all fines, fees and restitution.

The House bill would potentially keep hundreds of thousands of former felons from voting. The Senate’s version is milder, allowing felons to vote while paying off fines and fees.

Both Galvano and Sen. Jeff Brandes, R-St. Petersburg, the architect of the Senate bill, said Friday they were willing to consider the House version, which Brandes said was constitutional.

And the Republican leaders of both chambers said they remain committed to passing a bill this session. The question is whether the House, the more conservative chamber, is willing to accept what the Senate offers.

“We’re going to work through the weekend to see what the right position is, and what we can get the votes for,” Brandes said. “I don’t think it’s a done deal.”

If the Senate adopts the House version, it would be a devastating blow to supporters of Amendment 4, the historic expansion of voting rights that would have allowed felons to vote if they completed “all terms of their sentence including parole or probation.” Previous estimates put new potential voters from felons at more than 1 million.

Creators of the amendment objected to lawmakers passing any bill, but after weeks of talks with Brandes, who has championed criminal justice reforms over the years, they eventually supported the Senate’s bill.

That measure doesn’t require fees and fines be paid if they were converted to a civil lien. Since fees and fines are usually converted to a civil lien by the time a felon has completed their probation or parole, it would allow them to vote while paying off those obligations, as many other states allow.

The Senate bill had won support from Desmond Meade, the former felon whose grassroots organization helped convince nearly 65 percent of voters to adopt the bill last fall.

“We look forward to standing with the Senate as they stand with the voters of Florida,” he said in a statement Friday.

Brandes said he supports the Senate’s version, which he said had “grace,” but he emphasized the constitutionality of the House bill.

“It’s fair to say it encompasses the ideas by which they proposed this amendment, and publicly supported this amendment,” Brandes told the Times/Herald. “I think ours is fairer to felons.”

Galvano indicated Friday that he would heavily defer to Brandes’ judgment on the high-profile bill, which has prompted high-profile Democrats to blast as a “poll tax” — a reference to the Jim Crow-era practice of charging a fee to black voters to deny their access to the ballot box.

“He said it’s not quite everything we had in the Senate side, but he said it does follow the letter of the law,” Galvano said.

The House bill sponsor, Jamie Grant, R-Tampa, said he would negotiate with Brandes and others over the weekend. The House considers fees, fines, and restitution to victims as part of someone’s sentence under the amendment. But Grant said he feels the House version is fair, since it allows judges to throw out someone’s financial obligation if they want to.

“The worst possible outcome for folks looking to have rights restored under Amendment 4 is no bill,” Grant said. “That would be a travesty. I think on both sides of the chamber, we’re committed to having a bill we can present to the governor.”