After the US military installed the THAAD missile system in South Korea, Trump is now charging Seoul $1 billion for the anti-missile battery. The South Korean government rebuffed Trump's demands, almost disregarding it altogether.

Trump also wants to re-examine free trade deal as well

As Trump's policy is to renegotiate every deal made by the Obama administration if possible, the trade agreement with South Korea is now on his radar. Trump said that either Seoul agrees to renegotiation, starting with the purchasing the Thaad system or face termination of the free-trade deal with the US, which he calls "horrible."

The THAAD system was among the deals made by the previous administration on bolstering the South Korean defense against possible attacks from the north.

The deal states that South Korea will provide the site, while America will pay for the deployment of equipment, in this case, the THAAD missile system.

Trump wants to reexamine this deal and find ways to change it so that South Korea will pay an amount almost to $1 billion for the advanced anti-Missile Defense System installed in their country.

Trump's THAAD sale is not what the Defense Department wants

If Trump desires the anti-missile system be sold to South Korea, the US defense department wants to retain the ownership of the advanced weapons system. This is why many believed that Trump's statements of selling the THAAD system to South Korea is a negotiation tactic to bring Seoul to the renegotiating table.

The THAAD system is included in the KORUS deal, which Hillary Clinton closed and approved by Congress in 2011. Nevertheless, Seoul's foreign policy adviser Kim Ki-jung said that the deal Trump wants is an impossible deal. This is because even after Seoul purchases the missile system, its operation will still be conducted by the US military.

Seoul was caught off-guard by Trump's sudden renegotiation

South Korean vice trade minister, Woo Taehee said that they were not notified of any trade renegotiation with the United States. The KORUS or Korean-US free trade agreement is the main focus of Trump's sudden change of talk with South Korea. This is a trend in Trump's agenda of revamping trade agreement deals negotiated by the previous administration.

At the moment, the THAAD system installation is in the process, and it will be effective in the few days. China and Russia, on the other hand, have started planning their own anti-missile system in response to THAAD.