Many of the local hardline Protestants are now estranged from her, blaming her for her party's role in limiting the flying of the Union Jack at Belfast's city hall. Their anger erupted in dozens of riots and hundreds of other protests.
The offices are picketed for at least an hour a day by a small band of loyalists who since December have been turning up, hail, rain or snow, to denounce her.
"Some days they can be very quiet, just standing there," said Long, "But other times they can be more aggressive and abusive. It's variable."
Outside the office a dozen of those constituents, including two middle-aged women wearing union flags as cloaks, maintain a a vigil in the cold, watched by the police in the Land Rover. They complain vociferously that during protests "the cops beat us into the ground".
They add heatedly, with much finger-pointing: "It's our flag, it should still be flying. Naomi Long can go to hell - she brought it all on herself."
So what do they think of their MP? "I can't say it out loud," spluttered an older man. "Not in front of the women here."
Long says: "I'm not being reckless with my personal security, partly for the safety of my family and also for the police - I don't want to put them in harm's way ...
"We're operating as normally as you can in these circumstances."
The flag roadblocks and rioting cost Belfast dear in terms of its recent reputation as a city in transformation.
Long describes the damage as immense, with policing costs alone reaching £20 million ($36 million).
Well over a hundred loyalists will now face charges. "One of the saddest things," according to Long, "is that we have young teenagers who will walk away from this with nothing more to show for it than criminal records. That will hang over them for the rest of their lives."
Alliance is a middle-of-the road party, known mainly for its moderation and belief in compromise, but the flag dispute has thrust it into a major firestorm. Long strongly advocates integration in areas such as housing and education.
Long is an optimist but she has worries. "We don't have forever to get relationships sorted, or we'll have another generation of young people who are embittered, with an anger against those on the other side."
-Independent