Britain's departure from the 28-member European Union may be the start of something bigger, and far more chaotic.

Brexit has roiled world markets and divided other E.U. members, amid rumblings of other countries wishing to hold a vote on continued membership. One former diplomat told CNBC that the process of Great Britain leaving the community of European nations, which may take years, is likely to be fraught with peril and tension.

"It will be a messy divorce between the United Kingdom and the E.U.," says Richard Haass, president of the Council on Foreign Relations. So could Brexit be the beginning of the end of the European Union itself?

"Quite possibly, if not the end of it, certainly the change of it," the former State Department official told "On The Money" in a recent interview.

"The scary thing, the frightening thing about this vote is it may have set in motion trends (in) which the entire E.U. itself," Haass predicts, "will begin to unravel."

Haass, a Republican and former State Department director of policy planning, was a principal advisor to Secretary of State Colin Powell. He says other "exit" votes could be ahead, as populist movements in countries like France, Italy and Spain gain momentum.

"Other countries in the E.U. may want to have their own referenda, and the E.U. is wildly unpopular," Haass said. "I think it creates all sorts of questions about this thing called the 'European project'."

While Britain has been part of the European Union since 1973, the alliance had its beginning in the aftermath of World War II.

"The idea was to knit together in particular Germany and France so closely that Europe could never again become a venue of war," Haas told CNBC.

Not only could Brexit threaten the future of the E.U., Haas says it may destabilize the integrity of the United Kingdom itself: England, Scotland, Wales and Northern Ireland.

"I think what it will do is set in motion splits within the U.K. itself," Haass said. "Instead of being the United Kingdom, I think we'll going to see the beginning of the end of the country. "

Just two years ago, a Scottish referendum to leave the U.K. failed by a margin of 55.3 to 44.7 percent.

"I think Scotland will have another referendum, it will probably choose to go its own way, "Haass said, particularly because the region voted overwhelmingly to remain in the E.U. In 2015, Haass was an envoy for the Northern Ireland peace talks, and he added that Ireland could be next.

"People in Northern Ireland are going to want to unify with Ireland."

Although British voters decided to leave Europe, Haass warned it could also be their own country that actually sunders under the weight of a departure.

"I think this is really the beginning of the end of a country that's had a glorious history."

On the Money airs on CNBC Saturday at 5:30 am ET, or check listings for air times in local markets.