Back before the age of Twitter, a previous US president traveled to within spitting distance of North Korea and issued a stark warning about the nuclear aspirations of that country’s leaders.

“It is pointless for them to try to develop nuclear weapons, because if they ever used them it would mean the end of their country,” Bill Clinton said during a 1993 visit to the Korean Demilitarized Zone, standing closer to the North Korean border than any US president before him.

The North Koreans had plans of their own, however.

Five nuclear tests later, US Vice President Mike Pence visited the DMZ and the South Korean capital of Seoul this week, and he delivered a warning of his own.

“The era of strategic patience is over. If China is unable to deal with North Korea, the United States and our allies will,” Pence said.

The vice president told North Korea not to test the resolve of President Donald Trump, and Pence mentioned recent US airstrikes in Syria and Afghanistan as examples of what could be in store for the regime of Kim Jong-un if it stays on its current path.

“All options are on the table as we continue to stand shoulder to shoulder with the people of South Korea,” Pence said.  

Several times in recent weeks, President Trump has used his Twitter account to admonish the North Koreans.

North Korea is looking for trouble. If China decides to help, that would be great. If not, we will solve the problem without them! U.S.A.

— Donald J. Trump (@realDonaldTrump) April 11, 2017

Trump has also ordered an American aircraft carrier strike group to relocate to waters off the Korean peninsula, in what is widely seen as another pointed message to the North.

South Korea’s acting president, Hwang Kyo-ahn, on Monday said his government is speeding up deployment of the US anti-ballistic missile system known as “THAAD.”

The North Koreans just issued their own warning too.

"We'll be conducting more missile tests on a weekly, monthly and yearly basis," Vice Foreign Minister Han Song-ryol told the BBC.

Han said an "all-out war" would result if the US took military action.

"If the US is planning a military attack against us, we will react with a nuclear pre-emptive strike by our own style and method,” Han said.

Russia’s Foreign Minister Sergei Lavrov said Moscow would not tolerate any “nuclear missile adventures” by North Korea.

But Lavrov also chided the American vice president for “implying a threat of unilateral use of force that is a very risky course.”

In South Korea, most people seem to be taking everything in stride. Tensions on the Korean peninsula, going back decades, tend to rise and fall.

Related: If you’re young and South Korean, North Korea might not seem so scary

What is different right now though, according to James Kim of the Asan Institute for Policy Studies in Seoul, is that the Trump administration appears determined to find a new approach to North Korean leadership.

“We really haven’t seen an unpredictable administration making these threats to Pyongyang, to watch and see how Pyongyang responds,” Kim says. "It’s a good test, but it’s a dangerous one.”

South Korea is set to elect a new president next month. Kim says both of the frontrunners have suggested they would take a more conciliatory line with North Korea.

“Neither candidate has suggested that they’d like to break relations with the United States,” or even fundamentally alter the US-South Korean alliance, Kim says.

“We might see some choppy waters with a progressive administration, but it’s going to take a lot more than one election in South Korea — or, even for that matter, in the United States — to change the relationship that’s lasted for over six decades,” Kim says.

But Kim adds that many South Koreans are exasperated with North Korea’s provocative behavior and that they would like to see a stronger response.

There is a lot of public support for the deployment of the THAAD anti-ballistic missile system in South Korea, for example, and for the previous South Korean president’s decision to close the jointly operated Kaesong industrial park inside North Korea, Kim says.

“The South Korean public in general has come out and said, ‘We support these more hardline measures to deal with these problems,’” he says.

No one in South Korea really wants to go to war with the North, Kim adds. Instead, they are hoping that increased pressure might push North Korea’s young dictator, Kim Jong-un, to rethink his commitment to developing the country’s nuclear weapons program.  

From PRI's The World ©2017 PRI