“America will reclaim its rightful place as the greatest, most powerful, most respected nation on Earth, inspiring the awe and admiration of the entire world,” he said in his inauguration speech. “A short time from now, we are going to be changing the name of the Gulf of Mexico to the Gulf of America.”

It’s his latest suggestion to redraw the map of the Western Hemisphere. Trump has repeatedly referred to Canada as the “51st State,” demanded that Denmark consider ceding Greenland, and called for Panama to return the Panama Canal. Trump also spoke about taking back the vital waterway during his inaugural speech.

Here’s a look at his comment and what goes into a name.

Why is Trump talking about renaming the Gulf of Mexico?

Since his first run for the White House in 2016, Trump has repeatedly clashed with Mexico over a number of issues, including border security and the imposition of tariffs on imported goods. He vowed then to build a wall along the US-Mexico border and make Mexico pay for it. The US ultimately constructed or refurbished about 450 miles of wall during his first term.

The Gulf of Mexico is often referred to as the United States’ “Third Coast” due to its coastline across five southeastern states. Mexicans use a Spanish version of the same name for the gulf: “El Golfo de México.”

Americans and Mexicans diverge on what to call another key body of water, the river that forms the border between Texas and the Mexican states of Chihuahua, Coahuila, Nuevo Leon and Tamaulipas. Americans call it the Rio Grande; Mexicans call it the Rio Bravo.

Can Trump change the name of the Gulf of Mexico?

Maybe, but it’s not a unilateral decision, and other countries don’t have to go along.

The International Hydrographic Organisation — of which both the United States and Mexico are members — works to ensure all the world’s seas, oceans and navigable waters are surveyed and charted uniformly, and also names some of them. There are instances where countries refer to the same body of water or landmark by different names in their own documentation.

It can be easier when a landmark or body of water is within a country’s boundaries. In 2015, then-President Barack Obama approved an order from the Department of Interior to rename Mount McKinley — the highest peak in North America — to Denali, a move that Trump has also reversed.

Just after Trump’s comments on Tuesday, Marjorie Taylor Greene of Georgia said during an interview with podcaster Benny Johnson that she would direct her staff to draft legislation to change the name of the Gulf of Mexico, a move she said would take care of funding for new maps and administrative policy materials throughout the federal government.

How did the Gulf of Mexico get its name?

The body of water has been depicted with that name for more than four centuries, an original determination believed to have been taken from a Native American city of “Mexico.”

Has renaming the Gulf of Mexico come up before?

Yes. In 2012, a member of the Mississippi Legislature proposed a bill to rename portions of the gulf that touch that state’s beaches “Gulf of America,” a move the bill author later referred to as a “joke.” That bill, which was referred to a committee, did not pass.

Two years earlier, comedian Stephen Colbert had joked on his show that, following the massive Deepwater Horizon oil spill in the Gulf of Mexico, it should be renamed “Gulf of America” because, “We broke it, we bought it”.

Are there other international disputes over the names of places?

There’s a long-running dispute over the name of the Sea of Japan among Japan, North Korea, South Korea and Russia, with South Korea arguing that the current name wasn’t commonly used until Korea was under Japanese rule. At an International Hydrographic Organisation meeting in 2020, member states agreed on a plan to replace names with numerical identifiers and develop a new digital standard for modern geographic information systems.

The Persian Gulf has been widely known by that name since the 16th century, although usage of “Gulf” and “Arabian Gulf” is dominant in many countries in the Middle East. The government of Iran threatened to sue Google in 2012 over the company’s decision not to label the body of water at all on its maps.

There have been other conversations about bodies of water, including from Trump’s 2016 opponent. According to materials revealed by WikiLeaks in a hack of her campaign chairman’s personal account, former Secretary of State Hillary Clinton in 2013 told an audience that, by China’s logic that it claimed nearly the entirety of the South China Sea, then the US after World War II could have labelled the Pacific Ocean the “American Sea.”