Just hours after the nation's latest school shooting, the debate began anew: Are American schools built in a way that makes them easy targets? Are there too many windows, too many entrances and exits and too few security features?

The questions expose yet another divide, with Second Amendment activists and some security experts calling for safer school designs and some gun-control advocates saying it's a distracting side issue that avoids more meaningful action.

The debate began after the 1999 mass shooting at Columbine High School in Colorado and gained more attention in the aftermath of the 2012 shooting at Sandy Hook Elementary School in Newtown, Connecticut. On Friday, in the hours after a student shot and killed 10 people at a high school in Santa Fe, Texas, the state's lieutenant governor suggested again that it was time to examine school layouts.

"There are too many entrances and too many exits to our over 8,000 campuses in Texas," Lt. Gov. Dan Patrick said, explaining that those points can't all be guarded.

Gun-rights activists, led by the National Rifle Association, have pushed for a "hardening" of schools, including training and arming educators and even keeping shrubbery and landscaping farther away from school buildings so there are fewer blocked viewpoints. Reducing the number of entrances is considered another way to prevent shooters from getting inside undetected.

According to a report last year in Education Week, a trade publication, the average age of an American school is 44 years with major renovations dating back more than a decade. Older buildings were designed without today's worries of active shooters and terrorism.

They have lots of "nooks and crannies," isolated areas that are difficult to supervise, as well as old hardware on classroom doors and main offices that aren't located near the main entrance. Other problems include old public-address systems and no telephones in classrooms, said Kenneth Trump, president of the National School Safety and Security Services, a Cleveland-based consulting firm.

When it comes to designing schools, educational considerations create some natural tension with security needs. Studying in places with lots of light, for example, is thought to improve learning. That was the philosophy behind one school constructed just last year with floor-to-ceiling windows, Trump said. But those same windows could make students and staff easy targets for a gunman.

He agrees that a large number of entrances can make a school vulnerable. More doors bring a greater risk that someone will prop one open or that mechanical issues will prevent a door from being closed or locked. It's also harder to monitor who is coming and going.

And even if a front entrance is fortified with security systems, there are usually other ways in, such as the cafeteria where food deliveries are made or the gym.

Still, Trump said, no amount of architectural planning or design will replace mental health treatment, emergency drills and training and the ability to identify potential school shooters ahead of time.

It's simplistic to think that layouts and building features alone will make schools safer, he said, and politically expedient to tout only architectural design and construction.

Focusing solely on exits and entrances can create a host of other issues, cautioned Gregory Shaffer, a security consultant and retired FBI agent.

Having metal detectors at the entrance creates long lines, which means schools have to start earlier and hire more staff to screen students. "And if you have long lines going into the school, that makes it a target as well. That is a shooter's ideal location," he said.

For gun-control advocates, it's galling to focus on structural issues. They see frequent school shootings as evidence of the nation's unwillingness to take other steps to stop gun violence.

"I often find that the discussion of how to do it is really a smoke screen," said David Chipman, formerly of the Bureau of Alcohol, Tobacco, Firearms and Explosives and now a senior policy adviser with the gun safety organization founded by former Rep. Gabby Giffords, who was gravely wounded in a shooting in 2012. "How to do it isn't really the issue. It's do we want to do it and are we willing to pay the money."

After the 9/11 terror attacks, the United States took steps to secure government and public buildings — from airports to concert halls. It's routine now to go through a metal detector before entering. Yet those same steps aren't common in public schools, making them, he said, more dangerous than prisons.

"There are some places that we've decided as a nation that we will not allow violence to ever occur," Chipman said. "But school is not one of them yet."