"Terror has again gripped the establishment that the Trump who was elected president in 2016 might actually start implementing what he promised," Jatras, who was also once a US Senate foreign policy adviser, said on Thursday.
Trump needed to also overhaul the rest of his top-tier defense and national security advisers and chiefs, Jatras said.
Trump in a tweet earlier in the day commenting on his decision to withdraw US troops from Syria, said it was "time to come home and rebuild."
Earlier on Thursday, the Wall Street Journal reported that Trump has ordered the US military to withdraw some 7,000 troops from Afghanistan in the coming weeks.
The president made promises during his campaign to stop expending money and lives on foreign wars to rebuild the United States.