A new Pennsylvania State Police report on school safety reminds us of facts we already know:

• Many schools are vulnerable to the threat of a violent intruder armed with a weapon or a bomb and intent on taking multiple casualties.

• Current events around the world suggest schools across the United States are prone to terrorist acts.

• Schools can and should become habitual in their preparations to repel violent intruders and to minimize the threat.

The report was compiled by the state police Risk and Vulnerability Assessment Team. Since its inception in 2004, the team has assessed more than 300 public and private schools statewide, plus more than 30 college and university campuses. Their findings at these schools helped to shape the report released Monday.

And the key finding: There is no universal remedy.

“Unfortunately, there is no easy solution,” writes Col. Frank Noonan, state police commissioner, in an introduction to the report. “To foster a culture of school safety, everyone needs to be committed.”

The report stresses that all school buildings and cultures are different; they pose individual challenges and should respond to their challenges accordingly. But in general, there are some practical policies that apply to all schools. Its recommendations include:

• . Tightening access into school buildings by discouraging “piggyback entries” — authorized faculty or other employees allowing unknown individuals to follow them through a secured entryway; and tightening security around cafeteria kitchen entrances and loading docks.

• Establishing detailed lockdown and evacuation procedures.

• Assigning responsibilities and authority to specific administrative and security positions in the event of an attack. Establish chains of command and communication.

The general thrust of the report is to prepare ahead of time for the unthinkable, and to incorporate preventive vigilance into the daily routine — to make safe schools a habit.

No one follows this advice more diligently than school officials in Colorado, where shootings in three schools and a movie theater have occurred in recent years, most recently on Friday at Arapahoe High School in suburban Denver where a 17-year-old girl was critically wounded.

Previous incidents — most notably the Columbine High School massacre of 1999 — taught law enforcement a hard lesson. They learned it’s better to confront the assailants quickly and aggressively; at Columbine, a secure perimeter outside the school failed to stop the bloody attacks going on inside.

Colorado Gov. John Hickenlooper said an aggressive response to Friday’s attack probably saved many lives.

“It’s nice to see how well the system worked,” Hickenlooper said. “It’s a remarkable improvement from before. This could have been much, much worse.”

Colorado’s lessons are not wasted on Pennsylvania. A school attack can happen anywhere, anytime — a fact that makes prevention all the more difficult, but no less necessary.