"In Thailand, a close friend and ally, we are disturbed by the setback to democracy and hope it is a temporary bump in the road," Mr Kerry said at the East-West Centre in Hawaii. "We call on the Thai authorities to lift restrictions on political activity and speech, restore civilian rule and return quickly to democracy through free and fair elections."
After months of crisis diplomacy in the Middle East and Ukraine, Mr Kerry is taking up an initiative from President Barack Obama to reinvigorate diplomatic efforts in Asia and the Pacific. In the policy speech wrapping up his around-the-globe trip that included stops in Myanmar, Australia and the Solomon Islands, Mr Kerry outlined an ambitious policy that accentuated Asia's increasing economic importance to the US.
"The United States is an Asian-Pacific nation, and we take our enduring interests there very seriously," Mr Kerry said. "We know that America's security and prosperity are closely and increasingly linked to the Asia-Pacific."
The United States' long-term objectives for the Asia and Pacific region, he said, include promoting regional cooperation, resolving conflicts in the South China Sea, battling climate change and "empowering people" by standing up for human rights.
In that area, Thailand has been disappointing, he said. Unlike some of Asia's "bright spots," Thailand has been "backsliding" on democracy and found itself blacklisted on the State Department's latest progress report on human trafficking.
"We will continue to promote human rights and democracy in Asia, without arrogance but also without apology,'' he said.
After the coup, Washington cut $4.7 million of security-related assistance to Thailand and cancelled a number of training programs and exchanges with the military and police. The cuts, along with criticism from U.S. officials, has led coup supporters on social media and in the local press to call on Washington to stay out of Thai politics.
"We all know that some countries in the region hold different views on democratic governance and the protection of human rights," Mr Kerry said yesterday. "But though we may sometimes disagree on these issues with the governments, I don't think we have any fundamental disagreement with their people."
In neighbouring Myanmar, which Mr Kerry visited last weekend for the East Asia Summit, he noted that the country "still has a long way to go" toward full-fledged democracy.
Turning his attention toward China, Mr Kerry said that "by deepening its democracy, and preserving its traditions of tolerance, it can be a model for how Asian values and democratic principles inform and strengthen one another."
While acknowledging differences with the governments in the region on democratic governance and protecting human rights, he stressed that the differences on "universal and pragmatic" values were few.
"Given a choice, I don't think too many young people in China would choose to have less access to uncensored information, rather than more," Mr Kerry said.
The Associated Press, AFP, Bloomberg News, and Reuters contributed to this story.