Washington (CNN) At the age of just four years old, children in North Korea bow before giant portraits depicting the three supreme leaders of the Kim dynasty -- a ritualistic display of obedience that embodies Kim Jong Un's strategy to maintain his unquestioned grip on power, a former North Korean diplomat told US lawmakers on Wednesday.

Kim Jong Un, his father Kim Jong Il and grandfather Kim Il Sung have carefully cultivated the perception that they are divine rulers and consolidated power by sheltering the North Korean population from the outside world and manipulating the country's welfare system.

"Until now, the North Korean system has prevailed through an effective and credible reign of terror and by almost perfectly preventing the free-flow of outside information," according to Thae Yong-ho, a former high-ranking North Korean official who defected to South Korea.

Thae was number two in the North Korean embassy in London before he escaped with his wife and two sons, arriving in South Korea in 2016.

"As long as Kim Jong Un is in power, there'll be no chance for the world to improve the human rights issue" or to cancel "the nuclear program," he told CNN in January.

But while Kim has leaned on decades of brainwashing tactics to elevate himself as a "god," a growing curiosity about foreign culture and the increasing penetration of free-market capitalism have begun to pose an internal threat to his domestic system of control in recent years, Thae told lawmakers on the House Foreign Affairs Committee.

"There are great and unexpected changes taking place within North Korea. Contrary to the official policy and wish of the regime, the free markets are flourishing ... the citizens do not care about state propaganda but increasingly watch illegally imported South Korean movies and dramas," he said.

Kim has tried to quell the demand for outside information by opening his father's archive of foreign films -- most of which were produced in the former Soviet Union or other socialist nations, Thae said.

But the North Korean government has also made select western media content available including movies like "The Lion King," "Beauty and the Beast" and the cartoon "Tom and Jerry," he said, a sign that the ever-building flow of unsanctioned information into the "Hermit Kingdom" is a concern.

And that concern is rooted in the fact that Kim has not experienced the same detached and sheltered lifestyle of those he rules over -- a reality that if internalized by the general population could ultimately jeopardize his standing as a deity, Thae added.

Regime survival

While the US has tried to ramp up diplomatic and economic pressure on the North Korean leadership through additional sanctions and tough rhetoric, those efforts have done little to slow Kim's march toward developing a reliable nuclear-tipped long range ballistic missile.

And while China and Russia have both recently supported additional United Nations sanctions on North Korea, their willingness to use their influence over the regime to increase pressure remains in doubt.

Two senior administration officials insisted Tuesday that the Trump administration is still engaged in ramping up pressure on the North Korean government through diplomacy, despite Trump's tweet earlier this month that his secretary of state was "wasting his time trying to negotiate" with Kim.

Defense Secretary James Mattis said on Saturday that Washington "does not accept a nuclear North Korea" and said "any use of nuclear weapons by the North will be met with a massive military response, effective and overwhelming."

Kim has made it clear that he is willing to develop a long-range nuclear weapon at any cost and he views achieving that capability as the key to ensuring regime survival.

North Korean military officers have been trained to unleash a massive artillery strike on the South Korean capital of Seoul without hesitation at the first signs of an attack by the US, Thae said, noting that a retaliatory strike would result in massive casualties.

Why North Korea wants nukes and missiles North Korea has long maintained it wants nuclear weapons and long-range missiles to deter the United States from attempting to overthrow the regime of Kim Jong Un. Pyongyang looks at states such as Iraq -- where Saddam Hussein was overthrown by the United States -- and Libya -- its late leader, Moammar Gadhafi, gave up his nuclear ambitions for sanctions relief and aid, only to be toppled and killed after the United States intervened in his country's civil unrest -- and believes that only being able to threaten the US mainland with a retaliatory nuclear strike can stop American military intervention. Many experts say they believe North Korea would not use the weapons first. Kim values his regime's survival above all else and knows the use of a nuclear weapon would start a war he could not win, analysts say.

By attaining a nuclear capable intercontinental nuclear weapon, Kim hopes to blackmail the US into reducing its military presence on the Korean Peninsula.

If US forces were to leave the Peninsula, Kim believes foreign investment would soon follow, prompting the ruling class in South Korea to flee, which would neutralize the primary threat to his own regime, Thae said.

With a nuclear capability, North Korea would also force Washington to examine the extent of its military commitment to South Korea, particularly if the scenario forces the US to weigh potentially sacrificing an American city in return for protecting the entire South Korean territory, he added.

"Today, Kim Jong Un thinks that only nuclear weapons and ICBMs can help him avert the continuing disintegration of the North Korean system," Thae told US lawmakers on Wednesday.

"He also thinks that the existence of a prosperous and democratic South Korea so close to the border is, by itself, a major threat towards his dynasty. While Kim Jong Un has already long had the tools to destroy South Korea effectively, he also believes it is necessary to drive American forces out of the peninsula," he said.

Targeted information campaign?

The US could "touch the Achilles Heel of Kim Jong Un" by tapping into the societal shift within the North Korean population with a targeted information campaign that disseminates basic concepts of freedom and human rights, according to Thae.

While some North Koreans have developed an appetite for South Korean-produced entertainment, Thae said that the majority of content being consumed does not resonate past the point of sparking curiosity.

But by strategically producing and distributing tailor-made content that challenges the North Korean population to critically analyze their own living conditions, the US could counter the Kim regime's brainwashing operation over the long-term -- a move that could foster domestic dissatisfaction that may eventually help drive Kim toward a willingness to compromise, he said.

"These changes, however, make it increasingly possible to think about civilian uprising in North Korea," Thae told US lawmakers. "As more and more people gradually become informed about the reality of their living conditions, the North Korean government will either have to change and adapt in positive ways for its citizens, or to face the consequences of their escalating dissatisfaction."

In the short-term, however, neither the Trump administration nor Pyongyang have indicated they are serious about coming to the negotiating table and North Korea is rapidly developing the capability to not only attack South Korea but also threaten the continental US with a nuclear strike.

In the face of that emerging situation, Thae said he supports building on the momentum that has been achieved through additional diplomatic and economic pressure on the North Korean leadership in addition to strengthening cooperation with South Korea and the global community.

Thae also recommended that the US expand its use of "soft power" in an effort to ultimately convince Kim that his nuclear goal in unattainable but also offer a path forward that does not result in a massive loss of life.

By reaffirming its commitment to using military force but also presenting a clear alternative that would guarantee regime survival and alleviate some of the pressure that has crippled the North Korean economy, the US may be able to start a dialogue over denuclearization using Kim's emerging domestic issues as leverage, he said.

"Before any military action is taken, I think it is necessary to meet Kim Jong Un at least once to understand his thinking and to try to convince him that he would be destroyed if he continues his current direction," Thae said.

While there is no guarantee that Kim will ever be willing to abandon his nuclear ambitions, nor that domestic pressure within North Korea will pose a credible threat to the ultimate survival of his regime, Thae argues that the US should invest in every strategic possibility before using military force.

"We cannot change the policy of terror of the Kim Jong Un regime. But we can educate North Korean population to stand up by disseminating outside information," he said.