President Moon Jae-in vowed to prevent war at all costs in a speech on Tuesday marking the anniversary of the end of Japanese occupation in 1945. He said, “Any military action against North Korea should be decided only by South Korea and not by anyone else without the South’s permission.”

He also warned of tighter sanctions and more pressure unless the North stop nuclear and missile provocations. Sanctions were designed to bring North Korea to the negotiating table, not to raise military tension, he said. Moon reiterated his calls for the North to hold inter-Korean family reunion events and participate in the Winter Olympics the South will host in February.

He has made clear his opposition to a unilateral US military option. Without question, North Korean nuclear and missile issues must be resolved peacefully in any event. The nation cannot let others decide its future, all the more so if it is about war.

However, his assertion to prevent war at all costs rarely sounds convincing. It is questionable whether he has the ability to do so. His speech also lacked concrete strategies to keep peace.

North Korea on Tuesday took a step back from its threat to fire missiles toward the US island of Guam. The state-run North Korean Central News Agency reported that North Korean leader Kim Jong-un said he would watch the US’ conduct “a little more” after being briefed on a plan for the missile provocation.

It is unclear, though, if his decision to back off was intended to seek a diplomatic resolution or find more pretexts to carry out the provocation. Considering the North has in the past raise tensions to its advantage, it is clear he seeks to weaken international response or crack the US-South Korea alliance.

What made Kim back away from the attack plan seems to be tough US warnings of war and the collapse of his regime, not dialogue offers from the South. Defense Secretary James Mattis warned Monday it would be “game on” for war if North Korea fired missiles that hit the US or its territories.

The US has warned of war, which South Korea will prevent at all costs. Moon might have vowed to prevent war for the sake of the national interests. Of course, war must never break out, but conflicting messages may well be avoided. Cacophony in the alliance is what Pyongyang wants to hear but what Seoul should beware of.

While the US has given tough warnings even at a possibility of missile launches, South Korea has offered to the North to participate in the Olympics despite its threat to make the South “a sea of fire.” Given the grave reality that the entire nation is in the range of North Korea’s nukes and missiles, Moon should have shown his will to make the North pay the price for its provocations at any cost.

On the day Moon reaffirmed the peace line in the speech, Japanese Prime Minister Shinzo Abe spoke with US President Donald Trump by phone.

They reportedly agreed that dialogue for the sake of dialogue was meaningless and that more pressure on the North was needed.

Overtures of peace are commendable, but they sound hollow to Kim in the present situation. The North has already snubbed the South’s offers of dialogue, and yet Moon has made the same offers again, giving the impression the South is begging for talks.

The most effective diplomatic way to prevent war is to pressure the North hard enough to come to the negotiation table. Only if pressure should be intolerably hard, will Kim stop provoking and accept dialogue offers.

Preventing war is what all South Koreans hope for. But peace cannot be secured by begging and pleas. A country can be defended not by words and visions but by power and will.

Regrettably, Moon did not show his tough spirit to respond indomitably to North Korea’s military provocations through an airtight alliance and national unity.

The North will be dispirited when the South shows its internal and external unity and an unyielding will to defend itself.