Maryland Gov. Larry Hogan (R), flanked by Senate President Thomas V. Mike Miller Jr. (D), left, and House Speaker Michael E. Busch (D). (Patrick Semansky/AP)

Just weeks after a fatal shooting at a school in Southern Maryland, and with the nation focused on gun violence, the Maryland Senate gave final approval Thursday to a bill that would require a resource officer or police coverage for every public school.

But lawmakers do not know how much the mandate would cost or how it would be funded.

An amendment that mandates the officers was added to a larger school safety bill that would also require schools to have lockable classrooms and hold age-appropriate active-threat drills.

The measure, proposed after the shooting at Great Mills High School, is moving quickly through the legislature in its final days of the 90-day session. It now goes to the House of Delegates.

The original bill required resource officers or police coverage only for high schools, but the amendment that narrowly passed Thursday expanded it to all schools.

“We should be able to go back to our constituents, to quite frankly our families and friends, and say we at least passed a bill that says there are SROs or adequate police coverage for all schools,” said Sen. Michael J. Hough (R-Frederick), who offered the amendment.

Senate President Thomas V. Mike Miller Jr. (D-Calvert) said he approved of the idea but worried about the price tag.

“We have to figure out how we’re going to pay for this,” he said Thursday during a discussion on the floor.

John Woolums, director of government relations for the Maryland Association of Boards of Education, said he appreciated lawmakers’ effort to provide security coverage at all schools but acknowledged that it would be an “enormously expensive undertaking.”

Just 400 of the state’s 1,400 schools have resource officers, said Woolums, who has participated in a work group on crafting the bill.

“There’s going to have to be discussion at the local level with police and sheriff’s departments and county governments about how any expansion of school police services are going to be paid for,” Woolums said. “These are highly trained professionals who are in limited supply at the present, and they require additional training to work in the school setting.”

Woolums said the measure provides a holistic approach toward school safety, addressing the need for facility assessments, emergency plans and evaluations, and better coordination between local schools and law enforcement.

Also on Thursday, the General Assembly voted to override two vetoes from Gov. Larry Hogan (R), restoring two measures that will decide when and how schools are built and how educators are disciplined.

One bill would strip the three-member Board of Public Works of its authority to approve school construction projects, replacing it with an appointed board.

The bill’s proponents say it is an effort to remove politics from the process of awarding funds for school construction, while its critics say it is a political attack on state Comptroller Peter Franchot (D), a Hogan ally who has clashed with leaders in both chambers.

Hogan had vetoed the bill Wednesday, calling it one of the General Assembly’s “most outrageous and irresponsible actions.” But lawmakers said Thursday that Franchot and Hogan — who used a red marker to draw an “X” across the bill when he vetoed it — bear responsibility for politicizing the process.

“My green vote to override this veto is to reorient our conversation away from theater and back to the schools, to make sure our decisions are made on the merits of our projects and the needs of our school systems,” Maryland House Majority Leader C. William Frick (D-Montgomery) said on the floor.

Lawmakers also overturned Hogan’s veto of a bill that would change the procedure for suspending or dismissing educators by giving an arbitrator the final say, instead of the local school board.

Sen. Paul G. Pinsky (D-Prince George’s), who supports the bill, said the legislation ensures due process. But Sen. Robert G. Cassilly (R-Harford) said the measure “undermines the quality of education.”

Hogan called the bill a “radical attempt to strip away the duly authorized powers of local school boards.”

Minutes before the override vote, the atmosphere in the state House had been one of bipartisanship, as Hogan and the Democratic leaders of Maryland’s legislature celebrated Republicans and Democrats working together during a ceremonial bill signing.

“This is an example of what can be accomplished when we work together,” Hogan said before signing a bill to stabilize skyrocketing individual health insurance premiums.

Under the law, the state will tax insurance companies in Maryland, which are paying less in federal taxes this year because of an exemption in the recent overhaul of U.S. tax code, and use that money to pay the biggest claims.

“It was a very bipartisan effort,” said Maryland House Speaker Michael E. Busch (D-Anne Arundel). “Everything that government should be is in this package.”