When President Trump recently invited Philippines President Rodrigo Duterte to visit the White House, it reopened questions about conflicts of interest between U.S. foreign policy and Trump's business interests.

The two presidents are connected by a Filipino businessman. Duterte last fall named Jose E.B. Antonio as special trade envoy to the United States. Antonio is also in business with Trump, building a 57-story, Trump-branded residential tower in Manila.

In a 2012 promotional video for the skyscraper, Antonio gave this testimonial for Trump's reputation: "We believe that Trump exemplifies the best quality of real estate anywhere in the world. It also exemplifies luxury and it exemplifies exclusivity."

Trump returned the favor, praising Antonio and his company: "True professionals, they really know what they're doing. Trump Tower Manila is going to be something special."

Also on the video, Ivanka Trump said, "We feel very comfortable with the Antonio family as the developers of this project," and Donald Trump Jr. reminisced, "Over the years dealing with the Antonios, both on a personal level as friends, and on a business level, we've just had nothing but great times and great successes."

As part of the branding campaign, photos and a billboard of Ivanka Trump were used to sell units in the building.

Antonio's Century City Development Corporation, which owns the building, paid Trump royalties of $1 million to $5 million in 2015, according to the president's most recent financial disclosure report.

Trump continues to profit from the branding deal, even in the White House. Unlike other recent presidents, he retained ownership of his businesses after he took office.

Meanwhile, Duterte has waged a steady campaign of criticism and insults at the United States. With a Dirty Harry image from his support for extrajudicial killings of drug dealers, he picked fights with the Obama administration. At a press conference last October, he said, "So you can go to hell. Mr Obama, you can go to hell."

The White House did not respond to NPR's request for comment.

"It all just looks really bad," said Stuart Gilman, an international consultant on anti-corruption policies and former official at the Office of Government Ethics. "It looks like Trump is trying to simply protect his properties."

Gilman said that if the administration encourages "these autocrats" and makes Duterte feel special, "that will undermine our desire to have a stable Filipino government."

A conflict of interest like this has deeper implications as well, running the risk of upsetting the careful process used in Washington to make foreign-policy decisions.

To develop a specific policy, "major players in the administration think about it, they consult with Congress, whatever, papers are put forward," said Joshua Kirlantzick, a senior fellow at the Council on Foreign Relations.

He said an evolving policy is debated, refined and pushed forward, eventually reaching the top levels of the White House.

But he questioned what would happen if the process changed course without explanation. "It possibly could go in a different direction because of some business interest, it's going to leave everyone wondering; A: What was the point of the process? And, B: How do we have like a reasonable, thoughtful, honest policy-making process in the future?"

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