The 77-year-old Hart served two terms as US senator for Colorado and ran for President in 1984 and 1988. He withdrew from his latter bid for presidency after details of his extramarital affair with Donna Rice became public.
In 1998, Bill Clinton selected him to co-chair and panel on homeland security and since then he has served on various commissions for the US State Department, Defense Department, and Department of Homeland Security.
"I think Gary Hart is one of the real visionaries of our time, in terms of his ability to understand the forces at work in the United States and how they relate to the forces at work around the world," Jim Lyons, Bill Clinton's economic envoy to Northern Ireland from 1997 to 2001, told the Belfast Telegraph.
"I think anybody going to Northern Ireland trying to help faces stiff odds," said Lyons, who has recently published ‘Peace Meets the Streets,’ a book about his Northern Ireland experiences.
Lyons said that what Americans usually bring to tough negotiations is realistic optimism and an attempt to understand what the problem is
"Let's understand what the working pieces are to solve the problem. And let's solve the problem.
"And I think Gary comes to this with that sort of can-do attitude."
Said former Connecticut congressman Bruce Morrison, who served as an advisor and intermediary in the Irish peace process throughout the Clinton years: "It's good that Secretary Kerry wants there to be an American voice and wants there to be it to be someone that he feels close to, and that he can rely on.”
"And the fact that (Hart) hasn't been engaged particularly in the past on Northern Ireland can be a virtue in the sense that I don't think that anybody could reasonably attach any partisanship, in Northern Ireland terms, to his history."
One Washington insider with long-time involvement in Irish affairs said high-level US governmental attention in Northern Ireland affairs shouldn’t be taken for granted.
Northern Ireland, like lots of places around the world, tends to think that their problems are the biggest on the board. And they aren't," he said.
"The reality is we've got Russia and Ukraine, we've got Ebola, we've got Afghanistan, and ISIL. There are all kinds of problems."
Morrison doesn’t see an end to America's interest in Northern Ireland any time soon.
"There will always be 40 million Irish-Americans. And so there will always be an interest, “he said. “This is a big country. And we can walk and chew gum at the same time.”