Maryland Gov. Larry Hogan in February. (Linda Davidson/The Washington Post)

Not long ago, the United States led the world in confronting climate change. By the end of the Obama administration, thanks in part to the White House’s dogged persistence and nuanced diplomacy, 195 countries had signed the Paris climate accord.

For the first time, in a truly global pact, every country that contributes more than 1 percent of the world’s greenhouse gases, except Russia and Iran, agreed to reduce emissions. But President Trump has recklessly signaled that the United States intends to withdraw from that agreement.

A spokesman for Maryland Gov. Larry Hogan (R) said, “This is not an action the governor would have taken.”

That tepid ambivalence is not leadership.

True leaders picked up the reins of responsibility Trump relinquished. Twelve governors — from both major parties — put politics aside, joined forces and recommitted themselves to doing all they can to save our planet.

Virginia Gov. Terry McAuliffe (D), Delaware Gov. John Carney (D) and D.C. Mayor Muriel E. Bowser (D) all signed on.

Maryland’s governor? Absent.

If this were Hogan’s only transgression when it comes to Maryland’s natural resources, he might be excused. Unfortunately, it is the latest in a string of failures that threatens to make Maryland’s reversals on safeguarding the environment almost as abrupt and unconscionable as the president’s. Criminal referrals for environmental investigations, for example, have plummeted since Hogan took office — not because violations are down, but because there are fewer inspectors to find and report violations.

While governors along the East Coast sought deeper emissions cuts through the nine-state Regional Greenhouse Gas Initiative (RGGI), Hogan led the charge to block those changes. The Maryland legislature implored the governor to stand up to Trump’s budget cuts, yet Hogan stood silent as federal funds and programs to clean up the Chesapeake Bay were slated for elimination, jeopardizing a generation of progress to protect our state’s most valuable environmental asset. Even after environmental advocates and the General Assembly committed the state to reducing emissions 40 percent below 2006 levels by 2030, Hogan vetoed the Maryland Clean Energy Jobs Act, but legislators secured the votes to override his veto.

This deficit of state leadership could not come at a worse time. Every high schooler learns that the United States’ federalist structure was designed as a check on unfettered executive power.

That’s what Brian E. Frosh (D) is doing as he leads attorneys general from across the nation to stop Environmental Protection Agency Administrator Scott Pruitt’s assault on our natural resources. That’s what University of Maryland President Wallace D. Loh is doing when he commits to eliminating carbon-based energy purchases by 2020. And that’s what conservation groups including the Maryland League of Conservation Voters, Chesapeake Bay Foundation, Sierra Club and Maryland Climate Coalition are doing when they obtain veto-proof majorities for environmental action in the General Assembly.

It’s also what governors along the Eastern Seaboard are doing — Democratic and Republican, from New York’s Andrew M. Cuomo (D) to Massachusetts’s Charlie Baker (R) and Vermont’s Phil Scott (R). It’s what then-Maryland Gov. Martin O’Malley (D) did when he jump-started Maryland’s clean-energy economy and helped launch the RGGI. This is what the framers expected states would do if the nation faced an existential threat.

Hogan has alternated between silence and standing in the way. He likes to say he isn’t bothering himself with the politics of Washington. But indifference is inexcusable. For Maryland, restoring and conserving our natural resources are not just about symbolic stances and principles of federalism, they are also about public safety and the economic vitality of our state.

For an Eastern Shore that relies on agriculture and tourism, climate change presents a fundamental threat to those economies in ways that virtually no other state except California can appreciate. Maryland has, thanks to the majestic twists and turns of the Chesapeake Bay, a magnificent 3,200-mile-long coastline. So when it comes to extreme storms, coastal erosion and rising sea levels, climate change presents a peril to Maryland that few other states can fathom. When our state and our country need clarion leadership, our governor remains silent. The next generation needs us to speak up.

The writer served as policy director to first lady Michelle Obama and senior adviser at the State Department under Secretary Hillary Clinton and Secretary John F. Kerry.