Republican President Donald Trump and Democratic challenger Joe Biden clashed on Thursday over North Korean diplomacy and the coronavirus pandemic in their last debate prior to the U.S. presidential election on Nov. 3, as polls continue to show the odds are against the incumbent.

The 90-minute showdown followed the first presidential debate, a chaotic encounter in late September marked by interruptions and name-calling, as well as the cancellation of the second scheduled debate in the wake of Trump's infection with the novel coronavirus.

Combined photo shows U.S. President Donald Trump (L) and Democratic presidential nominee Joe Biden participating in the presidential debate on Oct. 22, 2020, in Nashville, Tennessee. (Getty/Kyodo)

The nationally televised event turned out to be what political experts called a more coherent debate, as rule changes were made to ensure some "uninterrupted" time for candidates and Trump took on a more civil attitude than the previous showdown.

Biden, the 77-year-old former vice president, started off by attacking Trump's handling of the pandemic, which has left more than 220,000 dead in the United States, and went on to highlight the failure of the summit diplomacy with North Korean leader Kim Jong Un that was aimed at ridding the country of its nuclear weapons.

"What has he done? He's legitimized North Korea," Biden said, alluding to Trump's meetings with Kim that took place three times from 2018 to 2019 -- an approach which sitting U.S. presidents have not taken in the past.

Biden also said Kim, who Trump views as his "good buddy," is a "thug" and that the consequences of the Trump diplomacy is that North Korea now has "much more capable missiles, able to reach U.S. territory much more easily than they ever did before."

North Korea has not tested an intercontinental ballistic missile since November 2017. But earlier this month, it showed off what appears to be a new type of ICBM in its military parade.

Biden, meanwhile, showed a desire to leave room for dialogue, saying he may agree to meet with Kim on the condition the North Korean leader "would agree that he would be drawing down" the country's nuclear capacity toward the denuclearization of the Korean Peninsula.

Trump argued that he has been able to forge "a very good relationship" with Kim, while touting the fact there has been no war with North Korea despite a period of heightened tension over its nuclear and missile threats.

On China, Biden said Beijing should "play by the international rules" and criticized Trump for poking his finger in the eye of U.S. allies, which the former vice president said he will work with to make the Asian economic powerhouse abide by the rules.

The debate has been seen as the last major chance for Trump, who has continued to stir controversy through his freewheeling governing style and divisive rhetoric on race and immigration, to appeal to voters beyond his base who would be crucial for his re-election.

A recent poll by The New York Times and Siena College has showed that voters prefer Biden over Trump, the 74-year-old former real estate developer, on almost all of the pressing issues at stake in the election, including the pandemic, and that Trump is even losing his long-standing advantage with regard to the economy.

Trump, who has repeatedly downplayed the threat of the virus, on Thursday maintained an upbeat view over the country's fight against the health crisis, saying that some spikes and surges seen in parts of the country "will soon be gone" and that a vaccine is coming "within weeks."

In a last-minute attempt to turn around his campaign, Trump has recently stepped up corruption allegations against the Biden family during his campaign rallies, based on a tabloid article suggesting Biden's son Hunter profited off the former vice president's influence in overseas dealings.

The article reported emails allegedly obtained from a laptop that Hunter had supposedly dropped off at a repair shop in 2019, but some major U.S. media have questioned the authenticity of the data.

Trump brought up the issue during the debate, which Biden shrugged off.

"I have not taken a penny from any foreign source ever in my life," said Biden, who served as a senator for more than 35 years before becoming the vice president under Barack Obama in 2009.

Some experts on U.S. politics expressed doubt that the latest debate event would be something that changes the tide.

"These debates are really about: did somebody make a cataclysmic mistake that it would change the vote? There wasn't really a cataclysmic mistake," said Bruce Cain, a political science professor at Stanford University.

"Unfortunately, if you think about it from the point of view from an independent voter, the needle isn't going to move one way or another," he added.

Millions have already cast their ballots by mail or in-person to avoid going to crowded polling places on Election Day amid the pandemic.

An early vote statistics website, maintained by a University of Florida professor, shows voters have already cast ballots equal to more than 35 percent of the total votes counted in the previous presidential election in 2016.

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