US Secretary of State Rex Tillerson promised India a new century of "strategic partnership" on Wednesday, accusing its Asian rival China of undermining international order.
Setting the stage for an upbeat visit next week to Delhi, Washington's top diplomat drew an explicit comparison between China and the world's "two greatest democracies."
Washington and India have been building stronger ties for some time, but Tillerson made one of the clearest cases yet for the "shared values" underpinning the relationship.
As such, the speech also amounted to a warning to great power rival China that Washington will build regional alliances to counter its ever-growing power.
"The United States and India are increasingly global partners with growing strategic convergence," he said.
"Indians and Americans don't just share an affinity for democracy. We share a vision of the future," he said, projecting the relationship into the next 100 years.
Promising greater prosperity and security in a "free and open Indo-Pacific," Tillerson did push India to open up its borders to more regional and US trade.
But his harshest words were for China, the Asian economic behemoth and the nearest rival to India's huge population and the United States' still world-leading economy.
"China, while rising alongside India, has done so less responsibly, at times undermining the international, rules-based order," Tillerson chided.
"China's provocative actions in the South China Sea directly challenge the international law and norms that the United States and India both stand for," he said.
Last month, the chief of India's army warned that China had been "testing our limits" in a recent border stand-off and warned that Delhi's forces must be ready for conflict.
India and China went to war in 1962 over the state of Arunachal Pradesh and China has maintained better ties with Delhi's foe Pakistan.
Tillerson did not directly address August's stand-off on the Doklam plateau in the Himalayas, which is claimed by both China and Bhutan, an ally of India.
But he vowed that that Washington "won't shrink from China's challenges to the rules-based order, or where China subverts the sovereignty of neighboring countries."
And he approvingly cited US Defense Secretary Jim Mattis' declaration "that the world's two greatest democracies should have the two greatest militaries."
Tillerson noted the Indian navy is now flying the American P-8 surveillance aircraft alongside its US comrades, and promised help developing a carrier-born strike force.
Tillerson was speaking to guests of the Center for Strategic and International Studies in Washington. He is due in New Delhi next week for talks with Indian leaders.