Opponents of Governor Haley’s bid for the presidency are seizing on her stumble over a question about the origins of the Civil War, hoping her failure to mention slavery as the cause will doom her surge against President Trump.

Last week, a poll by American Research Group Inc. found Ms. Haley within four points of Mr. Trump in New Hampshire, though other polls show her trailing further behind. She was riding high until a campaign event on Wednesday. “What,” a man identified as Patrick asked her, “was the cause of the United States’ Civil War?” 

In campaigns, the short sound bite penetrates, but Ms. Haley proceeded to say both too much and too little on what ought to have been a lay-up for a candidate in the Party of Lincoln. “Well,” she said after a six-second pause, “don’t come with an easy question,” to something she may not have realized was a trap.

“A man who uses a great many words to express his meaning,” said the 18th Century English writer, Samuel Johnson, “is like a bad marksman who instead of aiming a single stone at an object takes up a handful and throws at it in hopes he may hit.”

“I think the cause of the Civil War,” Ms. Haley said, lobbing her rocks, “was basically how government was going to run, the freedoms, and what people could and couldn’t do.” She then asked Patrick — who she later labeled “a Democratic plant” — what he thought caused the war, to which he replied that he wasn’t running for president.

Government, Ms. Haley said, raining stones on the crowd, “was never meant to be all things to all people,” and “doesn’t need to tell you how to live your life.” It was a fine treatise on the power of the state over the individual, but the topic was the Civil War and one its major casus belli was notable for its absence.

Patrick — it’s not known yet if he indeed was a “plant” — said he couldn’t believe Ms. Haley hadn’t cited slavery. The former United Nations ambassador asked what he wanted her to say about it before moving on to the next voter, but the question followed her. Soon after, President Biden rebuked her in a four-word tweet: “It was about slavery.” 

This was a stone Ms. Haley might have lobbed back at the man living in a glass White House. In 1987 in South Carolina, eying a run for president, Mr. Biden sought to curry favor by saying Delaware, which he represented in the Senate, had been a “slave state” during the Civil War. 

Two times as a 2008 presidential candidate, Mr. Biden repeated the “slave state” line as a point of pride. Ms. Haley might have cited those statements or just quoted President Lincoln who, in his second inaugural spoke of those enslaved by a “peculiar and powerful interest” that all knew “was somehow the cause of the war.”

As governor of South Carolina in 2015, Ms. Haley oversaw removal of the Confederate flag from capitol grounds, a move made easier in a state known for its Southern pride by the tragic, racist Charleston church massacre. She is also of Indian ancestry and has spoken of the discrimination she faced growing up in the Palmetto State.

The fact that the Democratic Party led secession would also have provided a fine retort. Instead — whether with an eye on voters with lingering affection for the Confederacy or because she tends to overthink — Ms. Haley slung none of these rocks at the bullseye. 

On Thursday morning, Ms. Haley was defiant. “Of course the Civil War was about slavery,” she told WTPL’s “Good Morning, New Hampshire” radio show. “We know that. That’s the easy part of it. What I was saying was what does it mean to us today? What it means to us today is about freedom.” 

Ms. Haley said, “That’s what that was all about,” except it wasn’t. This was more meandering, offering a stark contrast to Mr. Trump who is famous — or infamous — for blunt answers to questions a seasoned politician avoids. 

During these lean, end-of-year news days, expect this story to go marching on with strong legs. But the attention also provides Ms. Haley with an opportunity to make her case, if she hones her aim and uses fewer rocks to hit the target.