A stop sign altered to read “Stop All War” is seen at the corner of 13th and G streets Northeast in Washington on Thursday. The sign normally says “Stop All Way.” (Linda Davidson/The Washington Post)

What a difference a letter makes. Just last month, the words under the stop sign at the southwest corner of 13th and G streets NE simply let drivers know that vehicles moving in all four directions needed to brake at the intersection. Then someone painted over the last letter and replaced it with an “r.”

“Stop All Way” became “Stop All War.”

“Cool,” said a laughing Carol Hilliard, who was in her yard with her Doberman, Chloe, when the sign was pointed out to her. “It’s pretty creative.”

It is unclear who is responsible for this bit of street activism, which is against the law. But times like these — when President Obama is considering military action against Syria — appear to inspire provocative statements in the H Street neighborhood, a haven for hipsters.

More than a sign of the times, the altered sign is a symbol of the neighborhood’s emerging quirkiness. This type of expression is becoming more common there. In the spring, for instance, “Stop the NSA” graffiti appeared on sidewalks and street signs along 13th Street NE.

And just a few months ago, at the very same intersection of 13th and G NE, the face of a little girl was painted on the sidewalk. Hilliard, 41, recalled: “She looked so sad, but it was kind of cool because all the kids would walk by and wonder, ‘Why is she so sad?’

“But then, I guess, the city washed it away,” which made Hilliard sad.

H Street’s nightlife continues to buzz, but residents in this increasingly popular corridor are decidely less nocturnal. There are new families with small children and young professionals with happy dogs.

Perhaps it’s the diverse, tolerant mix that has produced the sort of peacenik pulse associated with the “nuclear free zone” of Takoma Park.

“Now the sign shows we’re a bit creative, thought-provoking,’’ said Gene Mirus, 43. “We’re using public space to create cognitive dissonance.”

The caper at 13th and G was apparently carried out in the middle of the day, no more than three weeks ago. So said Leland and Heather Morris, who were walking past the stop sign this week with their Dalmatian, Lottie. Leland, 38, said he was returning from the neighborhood farmers market when he saw two people — a man and a woman — affix the “r” to the sign.

He shrugged it off.

“I just thought this was different,’’ he said. “No one’s going to not stop because of the sign.”

There was a time when the defacement of public property elicited stronger reactions. More than a decade ago, graffiti throughout the city was more indecipherable, less wry and more likely to be a marker of gang territory. Longtime residents say they had sense of community but were more cautious back then.

Don, an 18-year resident who is still cautious about using his last name, saw the sign, smiled and shook his head.

“I don’t know what’s going on in this neighborhood anymore. I think [the culprits] are just being facetious. But I don’t know.”

About six blocks away, a women’s peace organization, Code Pink, has been organizing protests against possible military action in Syria. But they have nothing to do with the graffiti, said Noor Mir, the group’s anti-drone campaign coordinator.

“I don’t think anyone here believes in defacing public property,’’ Mir said.

She added, half-jokingly: “I kinda wish we did.”

A stop sign isn’t a bad place to start campaign messaging, said David Seitz, a professor at Penn State’s Mont Alto campus. Seitz, who studies visual symbols and public spaces, has seen “All Way” signs doctored across the country. Some have been changed to persuade changes in diet (“Stop Eating Meat”). Others encouraged hip-hop dances from the early 1990s (“Stop. Hammertime”).

“When we talk about a common thing like a stop sign, it’s an icon of everyday life and something we don’t notice, yet it carries so much power and meaning,’’ Seitz said. “They were transforming an ordinary thing into something special and unusual, a little treat, even if you disagree with what the message is.”

Reggie Sanders, a spokesman for the District Transportation Department, said that out of about 30,000 stop signs in the city, the one at 13th and G was the only one the agency knew of with a new antiwar message. When a complaint is received about a defaced sign, cleaners are dispatched to repaint it right away.

Nobody is complaining at 13th and G. This week, some drivers snapped photos. Some don’t notice the difference at all as they talk over a cellphone headset or bop to “Blurred Lines” on the radio. Ben Brock, whose mutt Buoy likes to stop at that corner, said he appreciated it.

“I used to live in Arlington, and stuff like this would never happen,’’ Brock said. “It’s uptight over there. This neighborhood is different.”