Both sides said after the meeting that they would try to strengthen ties that go back 182 years, but Russel stressed that Thailand would have to return to electoral democracy for their relationship to become fully productive.
"We care deeply about our relationship with Thailand, we care deeply about the Kingdom of Thailand, and want to continue to work together and to expand our cooperation in the years to come," Russel said.
"We want to see " and I made this case very clear " we want to see Thailand be successful, and that includes a successful return to democracy which will allow us to more fully realize the extraordinary potential of this great relationship," he added.
On Russel's previous trip to Thailand, in January 2015, he criticized the junta's curbs on democracy and met with Yingluck Shinawatra, who had been forced to resign from the prime minister's job shortly before the military ousted the government she had been leading.
Russel's actions at that time set off a wave of criticism from the junta's supporters that prompted some Thai media to brand the veteran diplomat an "ugly American." The Thai government protested that he had "wounded the hearts of Thais."
The recently arrived U.S. Ambassador to Thailand, Glyn Davies, has also taken heat for criticizing the junta's clampdown on dissent.
Police took up a complaint brought by hard-line royalists who accused Davies of defaming the monarchy after he voiced concern last month about long prison sentences under a law that criminalizes criticism of Thailand's royal family.
Police appear unlikely to pursue an investigation against Davies, who has diplomatic immunity. But the adverse response he provoked, despite prefacing his remarks with praise of Thailand's revered King Bhumibol Adulyadej, underscored the disconnect that increasingly weighs on America's oldest diplomatic relationship in Asia.