After hours of emotional debate Tuesday, Florida's Republican-led House appears ready to revise gun laws and overhaul school security in response to the massacre in Parkland that took 17 lives.

With a final vote Wednesday, the historic House action would follow Monday's narrow Senate passage of a three-day wait to buy a firearm, a minimum age of 21 to buy any gun and a voluntary statewide program to train school personnel to carry concealed weapons.

They are the first gun restrictions to be endorsed by Republicans since the party took control of the Legislature in 1996.

In a tense Capitol, student protesters staged a "die-in" and held signs that said "no armed teachers." The fathers of two Parkland victims returned to the Capitol to urge passage, trying to change opponents' minds.

The National Rifle Association kept up its opposition and accused House leaders of bullying lawmakers to vote for gun control in the session's final days.

For hours Tuesday, the 76-member Republican majority defeated every Democrat-sponsored amendment.

Democrats tried to outlaw assault weapons and large-scale magazines, tax ammunition, require background checks on all gun transactions, mandate safety improvements at pawn shops and gun stores and allow cities and counties to pass stricter gun laws than the Legislature.

All failed, largely along party lines.

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Perhaps the most contentious issue also remained intact even as the 41-member House Democratic caucus voted to unanimously oppose it: a provision that would allow school personnel to be trained as certified law enforcement officers and carry guns on campus to neutralize threats by active shooters.

The House voted 71-42 to leave the program intact.

Supporters predicted it would protect students from an active shooter, and opponents said it would make schools less safe and that Parkland students strongly resisted the idea.

"The legacy of the city of Parkland is going to be that we armed teachers," said Rep. Jared Moskowitz, D-Coral Springs. "It doesn't matter what the truth is."

One the eve of a final vote, the families of all 17 victims of the Parkland shooter urged legislators to pass the school safety bill saying "the issue cannot wait."

"You must act to prevent mass murder from ever occurring again at any school," the families wrote in an letter emailed to all 120 members of the Florida House on Tuesday.

"This issue cannot wait," the families wrote. "The moment to pass this bill is now. We must be the last families to suffer the loss of a loved one due to a mass shooting at a school. We demand action by the entire Florida Legislature to keep our schools safe."

The bill (SB 7026) also allocates $400 million for mental health, adds school security measures, including police officers in every school, and replaces Building 12 at the Parkland school where 14 students and three teachers were murdered on Valentine's Day.

Police would gain new powers to seek risk protection orders and confiscate guns from people who are a serious threat to themselves or others based on clear and convincing evidence.

The bill creates a new 16-member commission with subpoena power to investigate the shooting and the official response and make annual recommendations to the Legislature for five years.

With a final House vote set for Wednesday, the Legislature's Republican majority will not consider any ban on assault rifles like the AR-15-style long gun used in Parkland.

"Whenever we speak to the rights of people," said Rep. Jose Oliva, R-Miami Lakes, "I think we have to walk a fine line and be very careful."

A statewide Quinnipiac University poll released last week said 62 percent of Florida voters favor an assault weapons ban.

At least a dozen Republicans are expected to vote against the bill because of the restrictions, but House Speaker Richard Corcoran, R-Land O'Lakes, has predicted the bill's passage.

If the Senate bill clears the House with no changes, it goes to Gov. Rick Scott for his signature.

The highly contentious issue of guns has spawned an unlikely coalition of some of the Legislature's most conservative and liberal members, some of whom oppose restrictions on guns and others who demand more limits.

Democrats filed amendments to eliminate the so-called guardian program, to ban the sale of all assault weapons in Florida and to require universal background checks on gun buyers. The same proposals failed in the Republican-led Senate on Saturday.

Some Republican senators received jars of tar and feathers delivered to their offices as criticism for voting for gun restrictions. "The tar and feather enemy of freedom award," one jar was labeled. "From the children of Bradford County."

As debate in the House began, Scott was in Miami, meeting with area police chiefs. Law enforcement experts are divided on the question of putting more guns in schools.

After Scott repeatedly expressed opposition to arming teachers, the Senate amended the bill to exclude educators who exclusively teach in classrooms from being armed.

Florida's response is being watched closely across the country. Andrew Pollack and Ryan Petty, the fathers of Parkland murder victims Meadow Pollack and Alaina Petty, were at the Capitol to meet with lawmakers and urge passage of the legislation.

About a dozen college students staged a "die-in" outside the House chamber, lying on the floor and chanting "Our children are dying."

"They were killed in school," said University of Florida student Marcela Mulholland, 20, who grew up in Plantation and played volleyball games at Stoneman Douglas High School. "It's so outrageous they can't be here so we have to be those students that were killed."

As the House debate began, Democrats quickly focused on what they say are persistent loopholes in Florida's gun laws. For example, the three-day wait applies to sales by licensed dealers but not to private gun sales.

NRA lobbyist Marion Hammer sent an "emergency alert" to Florida members Tuesday morning, blasting the Senate's action and accusing House leaders of "trying to bully Second Amendment supporters to get them to vote for the gun control package."

By inference, Hammer's criticism was directed at Corcoran, a longtime NRA ally who backs the legislation and is considering running for governor in a primary where gun rights supporters are a significant voting bloc.

Democrats released a list of 81 gun control bills they have filed over the past 20 years in the Legislature. Of the 81, Republicans agreed to schedule 19 for hearings and two bills became law.

The safety package includes $1 million for a permanent memorial to the 17 victims at the high school in northwestern Broward County.

Rep. Carlos Guillermo Smith, D-Orlando, his voice breaking, asked Oliva why the Legislature didn't also propose a memorial for 49 victims of the Pulse nightclub shooting in Orlando in 2016.

"No act exists on its own," Oliva said. "Pressure builds as a result of these things. It is an accumulation of things like this that warrants action."

For more than two decades, Republicans have pursued a pro-gun agenda, such as expanding a self-defense law known as "stand your ground" and preventing doctors from asking patients about guns.

The so-called docs versus glocks law was struck down by a court as unconstitutional.

The final attempt by Democrats to rework the bill was a $1 million request for a memorial in Orlando for victims of the Pulse nightclub attack, the worst mass shooting in Florida history.

Republicans defeated the request on a vote of 67 to 49.

Times/Herald staff writer Mary Ellen Klas contributed to this report.