During a recent debate about one of six constitutional amendments on North Carolina’s 2018 ballot, General Assembly special counsel Brent Woodcox made an important observation: you don’t know what you think you know.

That is, if Republicans assume they will retain control the North Carolina legislature in perpetuity, or Democrats assume they will retain control of the governor’s office, they are making an unwise leap of faith.

Just weeks before the 2010 midterms, for example, Democrats thought it was highly improbable they would lose the General Assembly. Except for a brief GOP House majority in the mid-1990s, Democrats had run the place for a century. But thanks to well-run campaigns and voter discontent with then-President Obama, Republicans won 26 seats — one of the largest political swings in North Carolina history.

Similarly, in 2016 voters re-elected U.S. Sen. Richard Burr and clinched North Carolina’s 15 electoral votes for Donald Trump. Yet Gov. Pat McCrory lost his re-election bid to Democrat Roy Cooper by two-tenths of a percentage point.

Thus, you ought not to base decisions about, say, the constitutional separation of powers on assumptions about who will win future elections. An unpleasant surprise may await you.

Woodcox made this point in the context of a constitutional amendment on this year’s ballot that would change the way state judicial vacancies are filled. Right now, governors get recommendations but have essentially a free hand to pick whomever they wish, including justices to fill vacancies on the North Carolina Supreme Court.

If voters approve the constitutional amendment, however, there would be a multi-step process. First, a commission comprising appointees from all three branches — the governor, the legislature, and the chief justice — would vet prospects submitted by the public. The commission would then forward prospects they deem meritorious to the General Assembly, who in turn would forward at least two prospective judges or justices to the governor.

If the governor declines to appoint either option, the appointment would fall to the legislature or, if it has already ended its regular session, to the chief justice. The appointee would serve until the next available statewide election.

At the debate I attended — held at Salisbury’s historic Meroney Theater by the North Carolina Institute of Political Leadership, the Rowan Chamber of Commerce, and the statewide cable channel Spectrum News — Woodcox argued that this new system, by involving all three branches of government as well as the public at large, would be a major improvement over governors filling vacancies unilaterally.

The other amendment supporter on the IOPL panel, Sen. Paul Newton, R-Cabarrus, also urged a focus on the future rather than short-term partisan assumptions. “What we’ve got to build here is a framework that best serves North Carolina’s interests,” Newton said. “We’ve got to look long-term, and this is a very good way to strengthen our bench.”

The opposing panelists, Sen. Floyd McKissick, D-Durham, and state Democratic Party head Wayne Goodwin, were having none of it. “This whole merit selection process is completely devoid of merit,” McKissick said. “It was a political grab from the outset.”

McKissick and Goodwin repeatedly made the point that, as far as institutional powers are concerned, North Carolina governors are relatively weak by national standards. They’re right. According to the latest edition of Politics in the American States, a standard text, North Carolina’s governors are the second-weakest in the United States (Oregon’s are the weakest).

Why? In most states, governors run a larger share of the executive branch. They have much-stronger veto power. They have more control over budgeting.

In one key area, appointment power, North Carolina’s governors are right at the national average. The judicial-vacancies amendment would crimp that power a bit. Speaking for myself, I don’t necessarily object to involving the legislature in filling judicial vacancies. But I’d prefer to offset that loss of power by, say, giving the governor an item-reduction veto.

Don’t evaluate either idea based on who currently occupies North Carolina’s Executive Mansion. In this case, it is more practical to be theoretical.

John Hood (@JohnHoodNC) is chairman of the John Locke Foundation and appears on “NC SPIN,” broadcast statewide Fridays at 7:30 p.m. and Sundays at 12:30 p.m. on UNC-TV.