The Republican presidential candidates who participated in the first prime-time debate. (Staff/Reuters)

AMONG THE 17 Republican presidential candidates who debated Thursday , a handful seemed actually to be running for president — meaning offering positions that might allow them to win a general election and then govern. The rest were — well, doing something other than that.

Presidential politics in a democratic society is about determining how to honor principle in a world that demands practicality. It requires persuading voters who may not already be on your side and winning allies who do not already share your goals. Some candidates appear to regard these skills as signs of weakness or tantamount to treason. Others understand they will be essential for anyone who hopes to move into the White House in 2017. The common term for this understanding is “electability.” Another description would be “lives in the real world.”

Former Florida governor Jeb Bush condemned politicians who use illegal immigration as “a wedge issue,” an ugly problem on left and right that plays on ethnic divisions, and he reaffirmed his support for offering undocumented people an earned pathway to legal status. He also warned against divisive rhetoric and “creating a grievance kind of environment.”

Ohio Gov. John Kasich refused to be baited into a confrontation with Donald Trump and instead urged the audience to assess each candidate’s policies. One he was pressed to explain was his decision to expand Medicaid in his state, and he rose to the challenge admirably. He explained that offering health care to the poor can save money, by reducing unneeded visits to the emergency room and by keeping the mentally ill and substance abusers out of prison. Not incidentally, those goals are humane as well as pragmatic.

New Jersey Gov. Chris Christie presented a cogent defense of his plan to trim old-age entitlement benefits for wealthy seniors, explaining that the system must be shored up for the poor.

Sen. Lindsey Graham (S.C.), who was relegated to the 5 p.m. “happy hour” debate, didn’t try to hedge his ideological bets on global warming. “You can trust me to do the following: When I get on the stage with Hillary Clinton, we won’t be debating about the science, we’ll be debating about the solutions,” he said, before explaining that he’d encourage domestic natural gas development and energy efficiency.

Many on the GOP fringe will no doubt see these as examples of capitulation. What they should see are people who are willing to tell them reasonable things, even if they don’t want to hear some of them.

There were many other candidates who couldn’t muster the courage, were frighteningly out-of-touch, or both, with Mr. Trump far and away the lead offender. These Republicans offer a one-way ticket to political and policy disaster. Mr. Trump is not a credible candidate. His continuing insistence that Mexico is purposely sending criminals over the border, without a shred of evidence, is one of many disqualifiers. It’s not too late for other candidates to examine their own rhetoric and ask themselves if it also relies on emotion and reaction rather than reality and reason.