'Belfast' returns to the Troubles. Belfast shouldn't.

The opening scene of the movie "Belfast" is a panoramic, colorful shot of the vital city in today's Northern Ireland.

But then, zooming in on the close quarters of a working-class neighborhood, the picture fades to black and white.

It's meant to signify a shift in time, back to 1969. But it also reflects a black-and-white, binary Catholic/Protestant, republican (nationalist)/unionist axis that made the city not vital, but violent, as the 30-year conflict known as the "Troubles" began with a bang. Years of bangs, actually, as tight-knit communities unraveled, blown apart (at times, literally) in shocking sectarian strife.

The Troubles are seen through the previously untroubled, but now wizening, eyes of Buddy, a 9-year-old lad loved by his family, identified as he sees them: Ma, Pa, Granny, Pop, and his older brother, Will. Writer and director Kenneth Branagh balances what Pa calls a "civil war" with warmth and wit, be it Buddy's budding romance with a schoolmate, mesmerizing American film and TV that breaks the bleakness, and genuine love from his family — those under his roof and those rooted in the community.

"You're Buddy from Belfast, where everybody knows you," Pop says to his worried grandson. "The whole family will look out for you. And that's what will keep you safe."

His family, and neighborhood, did in fact look out for him. But in the real, not the reel, version of Belfast, few — especially innocents — were truly safe during the Troubles.

"There was an everyday terror in not knowing when there would be violence," said Anna Clark, a University of Minnesota history professor whose academic specialties include Irish history. "It was this kind of very visceral fear that drove people toward their own, rather than allowing for the more casual contact with each other."

The "fear of these bombs and a fear of having your house burned down, or someone coming in randomly shooting, put people on edge all the time," said Clark, who added that "It was really like living in a war zone."

A war zone where soldiers were in uniforms, but Protestant and Catholic combatants wore normal clothes (and sometimes ski masks). Despite the better-known role of the Irish Republican Army, it's not the IRA that's the threat to Buddy's Protestant family — it's Protestant paramilitaries.

Clark commented that even though there were Protestants who supported nationalism and many Catholics didn't back the IRA, religious differences "became part of community identification."

Some of this sectarian/community identification nexus has been sapped by Western secularization. But it's still omnipresent, and even ominous. Just last week a bus was burned near Belfast, and scattered riots broke out last spring, mostly in response to a Brexit-triggered trade dispute between the European Union and United Kingdom.

At issue is the status of the border between Northern Ireland and the Republic of Ireland, which has been mostly only in name since the "Belfast Agreement," (also called the "Good Friday Agreement"), negotiated with deep U.S. involvement, brought a fraught peace in 1998.

In response, the E.U. could nix the entire Brexit trade deal, spiraling the crisis into unknown waters, metaphorically and literally at a time when the British economy is already reeling. So what sounds like a technical trade dispute may actually spur a deep diplomatic rift between London and Brussels — and even Washington.

"Because the United States was so invested in the Northern Ireland Agreement, and because of the relationships with both Ireland and the U.K., not to mention our trade relationship with the E.U., I think this is something that should be of concern to the U.S.," said Mary Curtin, diplomat-in-residence at the Humphrey School of Public Affairs.

One of the cornerstones of the accord was an acceptance of a "sort of ambiguity about the border between Northern Ireland and the Republic of Ireland," Curtin said. "And anytime that delicate balance is threatened, even if it's over what seem to be arcane trade rules, that can spiral out and revive tensions that never really went away."

This crisis "was kind a self-inflicted wound by the British government," said John M. Roberts, a nonresident senior fellow at the Atlantic Council. Speaking from Scotland, Roberts reminded that a majority in Northern Ireland rejected Brexit in the 2016 referendum. "We haven't sorted this out, the consequences of the U.K. leaving. At its worst, it means that if you resurrect the border between the north, which is the U.K., and the south, which is the Republic of Ireland; do you bring back the Troubles? After all, close to half of the population of Northern Ireland actually believed it should be part of a united Ireland."

Roberts is quick to point out that no majority on either side favors violence. But "a hard border will be an extreme condition and promote extremism." On either side, Roberts said, "there is a middle ground. And it's the British government that's going to potentially lose the support of that middle ground."

There doesn't need to be now, either, if cooler heads prevail.

"Belfast" ends with an inversion of the same cinematographic trick it began with: A dissolve from the black-and-white of 1969 to vivid color of today's more prosperous, peaceful city.

A compelling, Oscar-caliber film, "Belfast" doesn't need a sequel.

Neither do the Troubles at the center of it.