Mr. Trump’s endorsement is the clearest evidence yet of his preference for authoritarianism as the best response to the problems of the Middle East, a sharp departure from the professions of support for democracy by previous American presidents of both parties.
Although this is not the first time Mr. Trump has praised an Arab strongman, his expression of support for Mr. Hifter appears to be the first time that Mr. Trump has embraced an aspiring authoritarian who is not yet in power and may never get there.
A former general under Col. Muammar el-Qaddafi and also a former C.I.A. client, Mr. Hifter had been living in exile in the United States but returned to Libya during the Arab Spring uprisings in 2011. He first declared his intention to seize power in 2014, when Libya’s nascent transitional government was struggling to establish its authority over freewheeling militias around the country.
Mr. Hifter vowed to rid Libya of Islamists of all kinds, and he quickly attracted support from Egypt, the United Arab Emirates and Saudi Arabia. All three had aligned themselves in a regionwide campaign to crush the Muslim Brotherhood-style political movements that had appeared poised to ride Arab Spring elections to power.
Mr. Hifter has never shown a willingness to accept any civilian authority. But “he fits to a T the kind of leader Trump likes to support,” said Andrew Miller, deputy director for policy at the Project on Middle East Democracy.
Even with the extensive backing of his foreign supporters, though, Mr. Hifter has often struggled for military gains, taking three years to control the city of Benghazi. Although he now controls most of eastern Libya, his surprise advance on Tripoli has united the powerful militias from the western cities of Misrata and Zintan against him.
“I don’t think Hifter can do it,” said Lisa Anderson, a political scientist who has studied Libya and who was the president of the American University in Cairo during the uprisings of 2011. Although he may present himself as a strongman, she said, “he can’t actually control that part of the country and he will continue to face existential challenges there for the foreseeable future.”