House Democrat Rep. Joaquin Castro, the chairman of the House Foreign Affairs Oversight and Investigations Subcommittee, has opened an investigation into US Secretary of State Mike Pompeo’s decision to address the Republic National Convention.

In a letter to Deputy Secretary of State Stephen Biegun, Castro opined that Pompeo’s appearance is “highly unusual,” unprecedented, and arguably legal. “American people deserve a full investigation,” Castro wrote.

The nation’s first diplomat is currently traveling overseas. He is on an official trip to the Middle East to strengthen the US-backed deal to normalize bilateral relations between Israel and the United Arab Emirates.

“Looking forward to sharing with you how my family is more SAFE and more SECURE because of President Trump,” Pompeo tweeted on Sunday, adding: “See you all on Tuesday night!”

Pompeo is expected to address voters back home this week and deliver a recorded video message from the holy city of Jerusalem. His controversial decision breaks with Pompeo’s own instructions to his staff earlier this month to avoid engaging in political activities.

Besides, such a speech would compromise the independence of the agency he leads, Democrats said. Pompeo’s speech will also break with past precedent of sitting secretaries of state not addressing political conventions. It does not comply with the long-standing protocol of not discussing domestic issues while abroad.

According to Castro, Pompeo’s move would violate the Hatch Act, according to which federal employees are not allowed to take part in partisan political activities while on duty, wearing a uniform or using a government vehicle. Castro asked the second-highest ranking diplomat to reply to his complaint by Sept. 1.

A spokesperson for the State Department defended Pompeo’s actions saying that he would deliver the speech in a personal capacity and that no taxpayer money would be used for it. The spokesperson also added that Pompeo’s personal lawyers, State Department and White House lawyers cleared the address.

According to internal sources, President Trump asked Pompeo to speak at the event, and he considers it a great honor. The speech is about to take four minutes, sources noted. It would reportedly highlight the achievements of the US foreign policy under Trump, including the Middle East policy, strengthening NATO, seeking relations with North Korea, and more.

Past secretaries of state from both political parties, including John Kerry, Hillary Clinton, Colin Powell, and Condoleeza Rice never addressed their party’s conventions while in office. Nick Merrill, a spokesman for Clinton, said that she never did it too as it was not the State Secretaries do. ”Their job is to serve the American people, no their party’s delegates,” Merrill noted.

What do you think? Shall Pompeo address the delegates at the Republican Convention despite the criticism?