Mark Sandy, from the Office of Management and Budget, arrives to the U.S. Capitol earlier this month for a deposition regarding whether President Trump ordered a hold on military assistance to Ukraine. Sarah Silbiger/Getty Images hide caption

David Welna
A budget staffer is to become the first White House official to testify about Ukraine aid in the impeachment inquiry at the Capitol on Saturday. Joshua Roberts/Reuters hide caption
President Trump and Turkey's President Recep Tayyip Erdogan take part in a joint news conference during Erdogan's visit to the White House on Wednesday. Jim Watson/AFP via Getty Images hide caption
News Brief: Public Impeachment Hearings Begin, Erdogan Visits White House
A Russian Tupolev Tu-154 Open Skies Treaty reconnaissance aircraft sits on the runway at Elmendorf Air Force Base in Anchorage, Alaska, in 2004. Mark Farmer/AP hide caption
A U.S. military vehicle drives past an oil pump jack in the countryside of Syria's northeastern city of Qamishli. President Trump is leaving some U.S. troops in Syria, with the goal of controlling Syria's oil fields. But legal experts say exploiting the oil could amount to pillaging — a war crime. Delil Souleiman/AFP/Getty Images hide caption
Trump Administration's Interest In Syrian Oil Fields Raises Questions
Mazloum Abdi, commander-in-chief of the Syrian Democratic Forces speaks to reporters near the northeastern Syrian Hassakeh province on Thursday. AFP via Getty Images hide caption
Actress Lori Loughlin and husband Mossimo Giannulli exit the Boston federal courthouse after a hearing on August 27. Joseph Prezioso/AFP/Getty Images hide caption
In this Oct. 23, 2018 file photo, Defense Secretary Jim Mattis speaks beside President Donald Trump, during a briefing with senior military leaders in the Cabinet Room at the White House in Washington. Manuel Balce Ceneta/AP hide caption