In a speech that may preview a 2028 run for the presidency, Secretary of State Marco Rubio called on Wednesday to rebuild the Western alliance or face a future of “atrophy and servitude and decline.”

Speaking in Athens with the setting sun dramatically lighting the Acropolis behind him, Rubio invoked the ancient Greek concept of “thumos,” which he described as “the fire of passion, strength, courage, pride” at “the heart of great civilization.”

“Today, too much of the West has forgotten this quality,” he said. “Over time, we in the West came to feel ashamed of the very things that made us exceptional.”

Rubio traced the cultural legacy of the West through ancient Greece, the rise of Christianity, the Age of Discovery and the founding of the United States and drew a connection between the ethos of self-sacrifice that united the peoples of the West from the Spartans at Thermopylae to “St. Thomas More to the Battle of the Alamo.”

He contrasted that ideal with those of “the radical mullahs of Iran, whose cult of death hails child suicide bombers as national heroes and portrays martyrdom as an end to itself.”

Rubio said in a Spanish-language interview with a Colombian broadcaster in September that he has “no plans at this time” to run for president in 2028 after the end of U.S. President Donald Trump’s second term.

He, along with Vice President JD Vance, are widely considered to be among the potential frontrunners for the 2028 Republican nomination.

In his speech in Athens, Rubio said that the next decade, which would coincide with the next two presidential terms, was a “crossroads” at which “the decisions we make will write the story of the next century.”

“The course we take will determine whether the West maintains its place at the head of the world, or resigns itself to a future of atrophy and servitude and decline,” he said. “We will either choose to act now, or lose the choice to act at all.”