President Trump speaks about the U.S. response to Iranian missile strikes at a news conference with Vice President Pence, right, and Defense Secretary Mark T. Esper. (Michael Reynolds/EPA-EFE/Shutterstock)

The conflict between Iran and the United States appears to be de-escalating, with attention turning to how President Trump made the decision to kill Iranian Quds Force commander Qasem Soleimani.

Because of the administration’s heavy turnover, many in Trump’s circle of national security advisers assumed their roles within the past year.

Some key positions are filled only in an acting capacity, including the director of national intelligence and secretary of homeland security, which both require Senate confirmation to fill permanently.

Presidents typically assemble a “war cabinet,” similar to the National Security Council, to respond to crises. President George W. Bush called together such a group in the days following 9/11.

So who might be advising Trump? Most of the positions on the chart below are the ones that Bush called upon for his own war cabinet. He included roles like press secretary and attorney general that don’t necessarily require national security experience but can still be critical during times of conflict. (The Department of Homeland Security — created in response to the attacks — did not exist at the time, but its secretary is included here.)

When Trump’s national security officials started their jobs

President Trump has been in office for almost three years. As of Jan. 9, more than half of his key national security officials have been in their jobs for less than half that time.

Secretary of homeland security Chad F. Wolf (Acting)

TRUMP’S FIRST YEAR

SECOND YEAR

THIRD YEAR

Chairman of the Joint Chiefs of Staff Gen. Mark A. Milley

National security adviser Robert C. O’Brien

Director of national intelligence Joseph Maguire (Acting)

Deputy Defense Secretary David Norquist

Defense Secretary Mark T. Esper

Homeland security adviser Peter Brown

Press secretary Stephanie Grisham

Attorney General William P. Barr

Chief of staff Mick Mulvaney (Acting)

Only a third of them have been in their roles for more than half of Trump’s time in office.

CIA Director Gina Haspel

Secretary of State Mike Pompeo

FBI Director Christopher A. Wray

Treasury Secretary Steven Mnuchin

Vice President Mike Pence

President Trump has been in office for almost three years. As of Jan. 9, more than half of his key national security officials have been in their jobs for less than half that time.

Secretary of homeland security Chad F. Wolf (Acting)

TRUMP’S FIRST YEAR

SECOND YEAR

THIRD YEAR

Chairman of the Joint Chiefs of Staff Gen. Mark A. Milley

National security adviser Robert C. O’Brien

Director of national intelligence Joseph Maguire (Acting)

Deputy Defense Secretary David Norquist

Defense Secretary Mark T. Esper

Homeland security adviser Peter Brown

Press secretary Stephanie Grisham

Attorney General William P. Barr

Chief of staff Mick Mulvaney (Acting)

Only a third of them have been in their roles for more than half of Trump’s time in office.

CIA Director Gina Haspel

Secretary of State Mike Pompeo

FBI Director Christopher A. Wray

Treasury Secretary Steven Mnuchin

Vice President Mike Pence

President Trump has been in office for almost three years. As of Jan. 9, more than half of his key national security officials have been in their jobs for less than half that time.

Secretary of homeland security Chad F. Wolf (Acting)

THIRD YEAR

TRUMP’S FIRST YEAR

SECOND YEAR

Chairman of the Joint Chiefs of Staff Gen. Mark A. Milley

National security adviser Robert C. O’Brien

Director of national intelligence Joseph Maguire (Acting)

Deputy Defense Secretary David Norquist

Defense Secretary Mark T. Esper

Homeland security adviser Peter Brown

Press secretary Stephanie Grisham

Attorney General William P. Barr

Chief of staff Mick Mulvaney (Acting)

Only a third of them have been in their roles for more than half of Trump’s time in office.

CIA Director Gina Haspel

Secretary of State Mike Pompeo

FBI Director Christopher A. Wray

Treasury Secretary Steven Mnuchin

Vice President Mike Pence

Among the newest officials: acting homeland security secretary Chad F. Wolf, who stepped into that role in mid-November; national security adviser Robert C. O’Brien, who started in September; and Joseph Maguire, the acting director of national intelligence since mid-August.