He alluded to reports in the USA press which said that last August, Trump asked foreign policy advisers about the possibility of invading Venezuela, which the Trump administration has derided as a corrupt, left-wing dictatorship.
Surrounded by his top military aides in a White House meeting less than a year ago, the Associated Press on Wednesday reports that President Donald Trump wanted to know why the U.S. military couldn't "just simply invade" the country of Venezuela.
This account of the previously undisclosed conversation comes from a senior administration official familiar with what was said.
They explained that military action would likely alienate Latin American governments who were working together to punish and ostracize Venezuelan dictator Nicolas Maduro.
Despite rejections of his idea by his top aides, Trump pushed back.
Trump nonetheless persisted. He pointed to the successful invasions of Panama and Grenada during the 1980s - countries which, together, have about 13 percent of Venezuela's population - as examples of successful military interventions in the region.
In August past year, President Trump raised fears of a nuclear war when he threatened North Korea with "fire and fury", at a time when the idea of him shaking hands with Kim Jong Un still sounded like a bad joke.
The next day, August 11, Trump alarmed friends and foes alike with talk of a "military option" to remove Maduro from power.
The public remarks were initially dismissed in United States policy circles as the sort of martial bluster people have come to expect from the reality TV star turned commander in chief.
But shortly afterwards, he raised the issue with Colombian President Juan Manuel Santos, according to the U.S. official.
Trump's advisers said no, as did Latin American leaders with whom Trump also raised the idea, CNN said. That official says President Trump asked why the USA couldn't invade Venezuela, but his advisers discouraged the idea.
Eventually, Gen. McMaster was able to persuade Mr Trump of how risky an invasion would be.
The White House declined any invitation to speak on the matter, with a National Security Council spokesman simply reiterating that the United States would not remove any potential action from the table.
Seated at dinner with four allies from Latin American countries, President Trump defied his advisers and asked about a military solution to Venezuela's troubles. The U.S. has also distributed more than $30 million to help Venezuela's neighbors absorb an influx of more than 1 million migrants who have fled the country.
The US, Canada and the European Union have slapped sanctions on Maduro and dozens of Venezuela officials over allegations of corruption, drug trafficking and human rights abuses.
"A military intervention on the part of the USA empire will never be a solution to Venezuela's problems", Maduro said.
"No, it is not a coincidence", Maduro said.
However, the United States president eventually failed to garner support for his plans both from the regional leaders and his own administration officials. Santos, a big backer of US attempts to isolate Maduro, said an invasion would have zero support in the region.
Venezuela has seen ongoing public violence since soldiers attempted to overthrow leader Nicolas Maduro last summer. "The concern is that it raised expectations among Venezuelans, many of whom are waiting for an external actor to save them".