PHOENIX — Donald Trump suggested Sunday that his new administration could try to regain control of the Panama Canal that the United States “foolishly” ceded to its Central American ally, contending that shippers are charged “ridiculous” fees to pass through the vital transportation channel linking the Atlantic and Pacific Oceans.

Panama’s conservative president José Raúl Mulino, who was elected in April on a pro-business platform, roundly rejected that notion as an affront to his country’s sovereignty.

The Republican president-elect’s comment came during his first major rally since winning the White House on Nov. 5. He also used his comments to also bask in his return to power as a large audience of conservatives cheered along. It was a display of party unity at odds with a just-concluded budget fight on Capitol Hill where some GOP lawmakers openly defied their leader’s demands.

Addressing supporters at Turning Point USA’s AmericaFest in Arizona, Trump pledged that his “dream team Cabinet” would deliver a booming economy, seal U.S. borders and quickly settle wars in the Middle East and Ukraine.

“I can proudly proclaim that the Golden Age of America is upon us,” Trump said. “There’s a spirit that we have now that we didn’t have just a short while ago.”

The president-elect opened the speech by saying that “we want to try to bring everybody together. We’re going to try. We’re going to really give it a shot.” Then he suggested Democrats have “lost their confidence” and are “befuddled” after the election but eventually will “come over to our side because we want to have them.”

Atop a list of grievances — some old, some new — was the Panama Canal.

“We’re being ripped off at the Panama Canal,” he said, bemoaning that his country “foolishly gave it away.”

The United States built the Panama Canal in the early 1900s, as it looked for ways to facilitate the transit of commercial and military vessels between its coasts. Washington relinquished control of the waterway to Panama on Dec. 31, 1999, under a treaty signed in 1977 under President Jimmy Carter.

The canal depends on reservoirs to operate its locks and was heavily affected by 2023 Central American droughts that forced it to substantially reduce the number of daily slots for crossing ships. With fewer ships using the canal each day, administrators also increased the fees that are charged all shippers for reserving a slot.

With weather returning to normal in the later months of this year, transit on the canal has normalized. But price increases are still expected for next year.

Mulino, Panama’s president, has been described as a conservative populist who aligns with Trump on many issues. Panama is a strong U.S. ally and the canal is crucial for its economy, generating about one-fifth of that government’s annual revenue.

Still, Trump said that once his second term is underway, “If the principles, both moral and legal, of this magnanimous gesture of giving are not followed, then we will demand that the Panama Canal be returned to the United States of America, in full, quickly and without question.”

“I’m not going to stand for it,” Trump said. “So to the officials of Panama, please be guided accordingly.”

He did not explain how that would be possible.

A short time after Trump’s speech, Mulino released a video declaring that “every square meter of the canal belongs to Panama and will continue to belong” to his country.