President Trump announced Tuesday that he will nominate retired Army Gen. John Abizaid to become the U.S. ambassador to Saudi Arabia, filling a vacancy that was spotlighted by the difficult diplomacy between the United States and Riyadh over the killing of journalist Jamal Khashoggi.

The post has been vacant throughout Trump’s presidency.

Trump and Secretary of State Mike Pompeo have blamed Senate Democrats for holding up nominations, but no one had been nominated for the job until now. Turkey, where Washington Post contributing columnist Khashoggi was killed last month, also has no U.S. ambassador.

Abizaid, best known from his time overseeing the Iraq War, is now a consultant and a fellow at Stanford University’s Hoover Institution. His selection emphasizes the importance Trump has placed on the military partnership between the United States and Saudi Arabia, a major customer for U.S. arms.

Trump has said he does not want to disrupt arms sales in protest of Khashoggi’s death but has promised unspecified consequences for Saudi Arabia. Khashoggi was a U.S. resident.

Saudi leaders initially denied any involvement by the kingdom in the death, but now acknowledge it was premeditated. King Salman and Crown Prince Mohammed bin Salman deny involvement.

Pompeo and Trump’s adviser, the president’s son-in-law, Jared Kushner, have handled discussions with Riyadh directly, assuming some of the tasks that might have been done by a confirmed ambassador. Currently, a career State Department diplomat is in charge at the embassy.

Last month, the Trump administration launched a public pressure campaign urging Saudi Arabia to end the conflict in Yemen amid growing opposition in Congress to U.S. military support for the kingdom’s war there.

Pompeo and Defense Secretary Jim Mattis called for an end to more than three years of conflict between Houthi rebels and a government recognized by Saudi Arabia, the United Arab Emirates and the West. U.N. officials have warned that the war has left half the population of Yemen, one of the world’s poorest countries, on the precipice of famine.

If confirmed, Abizaid would succeed Joseph Westphal, a former Pentagon official chosen by President Barack Obama.

Under the Obama administration, Abizaid was tapped in 2016 to advise Ukrainian Defense Minister Stepan Poltorak. The Pentagon said at the time that the retired general would offer advice as Ukraine sought to reform and modernize its armed forces to more closely resemble Western militaries found in the North Atlantic Treaty Organization.

Abizaid rose through the ranks to become the four-star chief of U.S. Central Command in July 2003, putting him in the position of overseeing the Iraq War a few months after the United States invaded and Baghdad fell. Over the next four years, he oversaw the conflict and operations in more than two dozen other countries, including Saudi Arabia, as insurgent violence escalated and the United States faced scandals including the abuse of detainees by U.S. soldiers at the Abu Ghraib prison near Baghdad.

More recently, Abizaid has advocated that the United States take a leading role in setting global norms for how drones are used by military forces and called for more transparency by the Pentagon involving them.

“The United States’ drone policies damage its credibility, undermine the rule of law and create a potentially destabilizing international precedent — one that repressive regimes around the globe will undoubtedly exploit,” he wrote in a 2014 opinion piece along with former Pentagon official Rosa Brooks. “As lethal drones proliferate, the future imagined above is becoming all too likely.”

Abizaid also has called for the United States to find moderate centers of power in the Middle East and work with them, taking an active role there overall.

“Sometimes you need to stand for something instead of saying it’s all up to them,” he said in a 2015 speech at the University of California at Berkeley. “We have to make ourselves reliable.”