WASHINGTON — After supporters of then-President Donald Trump stormed the Capitol on Jan. 6, 2021, ominous fencing was erected to protect surrounding buildings.

One of the buildings that needed protecting was the grand marble structure across the street from the Capitol: the Supreme Court.

But during oral arguments on Thursday over Colorado’s effort to kick Trump off the Republican primary ballot, the justices asked little about a key question in the case: Was Jan. 6 an insurrection?

Instead, the court looks likely to rule in favor of Trump on other grounds, allowing the justices to avoid taking sides on such a contentious issue.

Based on the two-hour oral argument, it appeared there was a majority that would find that states do not have the authority to enforce Section 3 of the 14th Amendment, which bars people who previously held government positions and “engaged in insurrection” from holding federal office.

Justices asked questions on all manner of legal technicalities, including whether the president is covered by Section 3 and whether Congress needs to pass legislation to enforce it. In skirting the insurrection question, they also probed who gets to decide whether an insurrection took place, with several suggesting states should not have that power.

The only justice to directly press the insurrection question was Justice Ketanji Brown Jackson, a liberal appointed by President Joe Biden.

Jackson asked Trump’s lawyer, Jonathan Mitchell, whether he would concede that his client had engaged in insurrection.

Mitchell pushed back, saying, “President Trump did not engage in any act that can be plausibly characterized as insurrection.”

An insurrection, he added, “needs to be an organized, concerted effort to overthrow the government of the United States through violence.”

Jackson appeared incredulous at the narrow definition of the term.

“So your point is that a chaotic effort to overthrow the government is not an insurrection?” she asked.

“This was a riot. It was not an insurrection,” Mitchell responded.

In finding that Trump was ineligible, the Colorado Supreme Court held that Section 3 does apply to the president and that Trump had engaged in insurrection.

Previously, a lower court judge had ruled that there was an insurrection but concluded that Section 3 could not be enforced.

That followed a five-day hearing in a lower state court in which evidence that was submitted included Trump’s tweets, videos of the events of Jan. 6 and the report issued by the now-defunct House committee that investigated the attack.

One recurring theme during the Supreme Court arguments Thursday was the sense of unease on the bench at the idea of the justices having to review a flurry of state court rulings like the one in Colorado barring not just Trump but future presidential candidates from running for office based on claims that they were involved in an insurrection.

Justice Amy Coney Barrett, one of Trump’s three appointees to the court, wondered how the justices were supposed to review the evidence that Colorado courts relied on in concluding there was an insurrection.

She wondered if the justices might have to “watch the video of the Ellipse” and draw their own conclusions, a reference to Trump’s speech on Jan. 6 in which he encouraged his supporters to march to the Capitol.

Justice Samuel Alito, a fellow conservative, seemed to be thinking along similar lines.

“Would we have to have our own trial?” he asked.

Alito was among several justices who expressed concern about other states reaching different conclusions to the Colorado courts, leading to a potentially chaotic election.

At times it appeared that the only person in the courtroom who wanted to speak about how to define an insurrection was Jason Murray, the lawyer representing Colorado voters who say Trump is ineligible.

“We are here because, for the first time since the War of 1812, our nation’s capitol came under violent assault,” he said during his opening remarks.

The attack, he added, “was incited by a sitting president of the United States to disrupt the peaceful transfer of presidential power.”

As far as the Supreme Court is concerned, whether that constitutes an insurrection is likely to remain an open question.