President Yoon Suk-yeol returned home Saturday, wrapping up his three-nation trip that covered two important events. One was the state funeral of the Queen Elizabeth II in London, and the second was holding summits with US President Joe Biden and Japanese Prime Minister Fumio Kishida.

Both events turned out to be less than desirable. And something unexpected also took place, taking Seoul's political scene by storm.

In a bad start to his trip, Yoon failed to visit the queen while she was lying in state, missing viewing the coffin on his first day in London due to traffic problems.

The main opposition Democratic Party of Korea called it a “diplomatic disaster.” Of course, this assessment might sound overblown, but what came next was more than a disappointment.

On his second stop, New York, he was supposed to attend the UN General Assembly and hold a series of bilateral summits on the sidelines. In particular, much attention was paid to Yoon’s planned summits with President Biden and Prime Minister Kishida.

It turned out that Yoon did not have a formal summit with Biden due to scheduling issues. Instead, they talked with each other for 48 seconds at an event in New York on Wednesday.

Then came the shocker. A video emerged of Yoon using foul language right after talking with Biden. Yoon’s use of graphic words captured in the video stirred up a huge controversy, as Yoon was initially believed to be referring to lawmakers of US Congress in relation to the Inflation Reduction Act, which is set to deal a severe blow to Korean carmakers.

The president's office denied Thursday that Yoon used vulgar language in reference to US Congress. It claimed he was talking about a political situation in Korea where the National Assembly is controlled by the main opposition party.

As Yoon did not explain what he meant by his profanity-laced words, it is still unclear whether he was indeed targeting Korean lawmakers, or something else. Nonetheless, the fact remains that Yoon was careless about opening his mouth in public places, and it was not the first time that he used a crude expression that sparked disputes.

A senior presidential official was quoted by a local media outlet as saying that it is “highly inappropriate to draw a link between private remarks and diplomatic accomplishments,” apparently in response to the criticism that painted Yoon’s trip as a diplomatic disaster. But even if what he said was supposedly a private conservation, the level of language was far below what's required for a national leader. More importantly, with many cameras nearby at the public event, Yoon should have thought twice before using such expressions.

The summit between Korea and Japan did not go well either. Given that relations between the two nations are frosty due to fierce disputes over wartime forced labor and other touchy issues, hopes were high that Yoon might have an opportunity to improve the problem-laden situation. Again, scheduling issues occurred, turning the summit into “informal talks” that lasted around 30 minutes. In a hurriedly arranged meeting, Yoon visited the venue of an event hosted by Kishida in New York, which also touched off criticism from opposition parties in Seoul.

A presidential official described the informal talks as "the first step toward producing tangible results.” But a closer look at what came out from the meetup reveals nothing substantial or meaningful, except that Yoon was quite desperate to meet with Kishida, who seemed unenthusiastic about the talks.

Given that Yoon’s hectic overseas schedule was predominantly tainted by his own foul language that shocked people and angered the opposition party members, he should realize that his careless words have people wondering whether he is fit to be a national leader.