Here in the United States, the word “governor’ primarily means the elected head of a state, as in Nathan Deal, governor of Georgia, now serving his sixth year in office. But it also has a secondary meaning:

“Governor: a device automatically regulating the supply of fuel, steam, or water to a machine, ensuring uniform motion or limiting speed.”

That too describes the role played by Deal in Georgia politics. On issues from taxation to guns to social policy, Deal has served as a valuable governor — a check on excessive speed, a regulating device — on some of the more dangerous and destructive instincts of his party. Look at neighboring states — Alabama, North Carolina and Florida, for example — and you’ll see governors unable or unwilling to play that role, and you’ll see states that have suffered for it.

In other states such as Louisiana and Kansas, you will find Republican governors with no personal, internal governors, elected leaders such as Bobby Jindal and Sam Brownback whose unchecked ideological fervor and political ambition have pushed their states into near-bankruptcy. Deal, to his credit, has steadfastly avoided such errors himself and guided others away as well.

The most recent example is Deal’s intervention into House Bill 159, intended by its original author to update and clarify Georgia law regarding adoption. Last week, in the Senate Judiciary Committee, the bill was hijacked to serve another purpose altogether. Committee members added language to the bill that would let private adoption agencies, working under state contract, refuse to allow adoption by caring, fully qualified same-sex parents if the private agency believes such adoptions are inappropriate or immoral.

In other words, the new version of HB 159 would legalize anti-gay discrimination carried out with taxpayer dollars.

In some environments, it would be easy for such a bill to gather political momentum and head toward passage, setting off a series of unpredictable consequences that include the likely loss of federal dollars. But in his roles as governor in both the political and non-political sense, Deal has stepped in quickly, mildly noting that “I would hope they would reconsider the addition to this language that could put the whole bill in jeopardy.”

That’s not a blunt veto threat, but it sends the appropriate message to Senate leaders, including Lt. Gov. Casey Cagle.

In his message, Deal cited the potential loss of federal funds should the bill pass, but personal beliefs about fairness may also factor into his position; he may also be motivated by a practical fear of HB 159 becoming to Georgia what the “religious freedom” bill became to Indiana and the “bathroom bill” became to North Carolina, making those states appear petty and punitive and thus inhospitable places for corporate investment. Given the national press that the HB 159 bill has already attracted, that is a very real danger.

With two years remaining in his final term, in some eyes Deal has yet to cement what some might call a legacy. He did manage passage of a critically important transportation-finance measure, but he did so by punting on the question of state support for mass transit. Last year, voters wisely rejected his effort to take power from local elected school boards and place it unchecked in the governor’s office.

But these days, it’s easy to undervalue leadership that recognizes trouble and knows enough to steer things in a wiser, more decent direction.