President-elect Donald Trump has recently discussed national security and diplomacy with retired Gen. John Kelly, the longest-serving Marine general in the military today, with nearly half a century of military service under his belt.

Although during his last press conference before retiring earlier this year the decorated general described his “greatest fear” as being offered a job in the U.S. government, Reince Priebus, Trump’s choice for White House chief of staff, told Meet the Press host Chuck Todd on Sunday that Kelly is being considered for secretary of state.

The Marine combat veteran could provide an unmatched and informed perspective in any Trump administration position dealing with defense, diplomacy, and national security, whether it is secretary of state or the the key White House post of Counterterrorism Advisor.

Gen. Kelly paid the ultimate price for his country and the protection of fellow Americans when he lost one of his sons to the war in Afghanistan, becoming the highest-ranking officer to lose a child in combat since 9/11.

Two of his sons followed their father into the Marine Corps. In 2010, terrorists in Afghanistan killed one of them, Robert.

Moreover, having served 45 years, he could only be succeeded by one other service member as the U.S. military’s longest serving general — Air Force Maj. Gen. Alfred Flowers, who served one more year than Kelly.

Gen. John William Vessey Jr., who also gave 46 years to the U.S. military, has been identified as the longest serving active duty soldier in the Army.

During his tenure, Gen. Kelly served and commanded other troops in various forms of conflicts from jungle warfare against communism in Vietnam War and urban battles against jihadists in Iraq to combating drug cartels in Latin America as well as the growing influence of Iran on the Western Hemisphere.

He became the first commander of the Pentagon’s Southern Command (SOUTHCOM) to really sound the alarm on the presence of Shiite Iran and its various proxies in Latin America, including the narco-terrorist group Hezbollah and the elite Iranian Revolutionary Guard Corps (IRGC).

SOUTHCOM is tasked with U.S. military activity in an area from the bottom of South America to Mexico’s southern border,

The retired general had been unafraid to criticize positions taken by President Barack Obama and his administration.

Gen. Kelly stood against the State Department when it attempted to downplay the expanding influence of Iran on the Western Hemisphere.

He has criticized various positions taken by President Obama, namely decisions regarding the U.S. wars in Iraq and Afghanistan as well as arguments made in favor of shutting down American military prison in Guantánamo Bay, Cuba.

As SOUTHCOM commander, he oversaw the facility.

While the president maintained a soft stance on illegal immigration, Gen. Kelly warned about the flow of Islamic terrorism-linked aliens into the United States along with undocumented immigrants from Latin America.

His warnings to Congress and the Obama administration appear to have fallen on deaf ears. The U.S. government denied multiple requests from Kelly for more funding for SOUTHCOM, the results of which remain to be seen.

Trump’s White House transition team appears to be well aware of Kelly’s eminence as a military chief who has led troops during some of the bloodiest days in Iraq, a diplomat who has dealt with various friendly and unfriendly foreign governments on the American continent and overseas, and a national security expert with first hand experience on threats U.S. homeland emanating from transnational criminals and terrorists found on the Western Hemisphere and beyond.

Trump and Gen. Kelly “had a frank discussion about the global national security situation in the United States and various areas of conflict in the Middle East,” noted a statement issued Sunday by the presidential transition team.

“Additionally, they discussed General Kelly’s diplomatic experience during his time as the Commander of the United States Southern Command in Latin America, and as a combat commander in various areas of conflict in the Middle East,” it added.

The Trump administration has not explicitly announced what position, if any, Gen. Kelly may hold.

Gen. Kelly Kelly retired earlier this year at age 66 as SOUTHCOM commander.