ATLANTA — Pete Buttigieg had a target on his back and no one really even tried to hit it.

The mayor of South Bend, Indiana, is at number one with a bullet in polls this week, including the gold-standard poll of all-important Iowa, so everyone expected he would bear the brunt of attacks in Wednesday night’s Democratic presidential debate, sponsored by MSNBC and The Washington Post.

Instead, the other candidates let Buttigieg off the hook over the nearly two-and-a-half hour debate.

California Sen. Kamala Harris, who had attacked former Vice President Joe Biden over race in an earlier debate, decided to give Buttigieg a pass over his campaign's use of a stock image of a black woman (who turned out to be Kenyan) to illustrate his plan to help African Americans.

The moderators teed Harris up for an attack on Buttigieg's core vulnerability — his weakness with black voters and racial tensions back home in South Bend — but she pivoted to a wider issue.

"I was asked a question that related to a stock photograph that his campaign published,” Harris said. “But listen, I think that it really speaks to a larger issue and I'll speak to the larger issue. I believe that the mayor has made apologies for that."

Harris went on to criticize the Democratic Party in general for taking black voters, especially women, for granted.

New Jersey Sen. Cory Booker, who is also black, jumped in by saying “black voters are pissed off” and said he was worried the party would nominate someone who "isn't trusted, doesn't have an authentic connection” with black voters.

But Booker didn’t name any names and then turned to attack Biden for opposing marijuana legalization — "I thought you might have been high when you said it” — saying nothing about Buttigieg specifically.

By now, the candidates are well aware that there’s a price to pay for going negative in a party that favors civility and is terrified about the primary damaging their nominee in the general election against President Donald Trump.

Sharp attacks have backfired for almost everyone who has tried them, so much so that the most aggressive candidates are no longer on the debate stage because their campaigns lost steam.

No one wants to be the first to attack Buttigieg, who is widely popular among Democratic voters. So they’ll probably wait to see if Buttigieg still has momentum before deciding whether to unload on him at next month's debate.

That’s how it worked for Massachusetts Sen. Elizabeth Warren.

Her turn in the barrel didn’t come until October’s debate, even though she had secured a front-runner spot by the September debate.

The entire stage piled on Warren last month to try to arrest her rise in the polls. Her polling then plateaued, letting Buttigieg, who shares her core voter base of college-educated whites, to take her place as the candidate with the wind at their back, especially in Iowa and New Hampshire.

But Warren has stubbornly refused to return fire, even when attacked, and her campaign has more or less ruled out all attacks on other candidates.

Buttigieg suggested a different approach.

The only candidate who made a direct attack on the mayor was Rep. Tulsi Gabbard of Hawaii. But he appeared to win the crowd back to his side and pummeled Gabbard’s question to him as “outlandish,” becoming the first candidate to hit her in a debate for meeting with Syrian dictator Bashar al-Assad.

If nothing else, the exchange, in the final moments of the debate, allowed a young candidate best known for being pleasant to bare fangs that many may not have known he had — a warning to those who may consider coming after him next.