President Moon Jae-in returned home Monday from the G-20 meeting in Germany, where he highlighted North Korea’s nuclear and missile threats.

The meeting of the world’s 20 biggest countries came shortly after North Korea test-fired what it claimed to be an intercontinental ballistic missile. The leaders’ discussions on the issue, however, fell short of expectations.

The G-20 leaders did not include North Korea in their joint statement, and instead the chair -- German Chancellor Angela Merkel -- mentioned in a news conference the need for the UN Security Council to take appropriate action.

Outside the G-20 forum, North Korea was a major issue in the series of bilateral talks involving Moon and other leaders of neighboring countries, such as US President Donald Trump, Chinese President Xi Jin-ping and Russian President Vladimir Putin. Few of the talks, however, were fruitful when it comes to working out an effective measure to rein in North Korea.

Moon’s trilateral talks with Trump and Japanese Prime Minister Shinzo Abe turned out a rare successful one as the three leaders -- while excluding the possibility of military action -- reached an agreement to put up “maximum pressure” on the Pyongyang government.

Elsewhere, Moon also emphasized the need for the international community to work together to deal with the North’s nuclear and missile belligerence. But he delivered some confusing messages as well.

Moon reiterated his call for a simultaneous pursuit of sanctions and dialogue regarding the North’s nuclear and missile threats. Granted, dialogue can proceed even between warring states, but one cannot help but ask the question -- was it proper for him to call for negotiation with the regime at a time when its latest provocation was still stirring the whole international community?

And given under the current situation, how may would have thought that the North would respond positively to any of Moon’s peace overtures? On his way to the G-20 meeting, Moon proposed the reunion of separated families, the North’s participation in the PyeongChang Winter Olympics and halting the use of propaganda loudspeakers along the inter-Korean border.

If those statements showed that Moon has yet to decide which way to go, sanctions or dialogue, the series of bilateral talks held on the sidelines of the G-20 meeting exposed the difficulty in reaching an international consensus on how to tackle the North Korean issue.

What had become obvious through the series of summit talks was that China and Russia were as strongly united in favor of North Korea as South Korea, the US and Japan were against it.

Both Xi and Putin made it clear that they did not want the international community to put further pressure on the North and reiterated their call for halting South Korea-US joint military exercises in return for the North’s suspension of its nuclear and missile testing.

Both Xi and Putin also called on Moon and Trump to cancel the deployment of the Terminal High Altitude Area Defense system in South Korea. Earlier, Putin’s Russia thwarted the US Security Council’s move to adopt a new resolution against the North over the July 4 missile launch.

These point to the possibility of a Cold War-like battle line forming between South Korea, the US and Japan on one side and North Korea, China and Russia on the other. It won’t be easy for Moon to navigate his North Korea policy under the circumstances.

In a meeting with Canadian Prime Minister Justin Trudeau, Moon called the situation “the worst crisis” since the 1950-53 Korean War. The dangerous situation may get worse if North Korea crossed the “red line” -- conducting a new nuclear test or test-firing a more sophisticated or a longer-range ballistic missile.

Moon needs to think about what he can and should do to prevent the North from crossing the red line. It is needless to say that he needs to think about what he should do when the North eventually crosses the red line.