Tim Kaine is a US senator from Virginia. He served as a federal appellate law clerk and then practiced civil rights law for 17 years in state and federal courts. The opinions expressed in this commentary are his.

(CNN) As a member of the Senate Armed Services and Foreign Relations committees -- and the father of a Marine -- my job is to minimize the risk of unnecessary war and maximize the chance that we will decisively win any war we must fight. And like many Americans, I am very disturbed that we may be drifting toward an avoidable war with North Korea.

Tim Kaine

Our national security experts -- including Defense Secretary Jim Mattis and Secretary of State Rex Tillerson — rightly point out that the US prefers diplomacy over war and is never out of diplomatic options. But President Donald Trump often undercuts them by tweeting out juvenile challenges to North Korea's leader Kim Jong Un or dismissing the prospect that diplomacy might work.

Throughout history, we have seen how back-and-forth provocations, mistakes and miscommunications can lead to large unintended conflicts. President Trump's rash actions raise the prospect of "war by accident."

We need to avoid a costly and catastrophic war on the Korean Peninsula. And creative diplomacy can help us do so. What must we do?

First, the President should quit raising the risk. He should cut out the inflammatory tweets. He should maintain a strong partnership with South Korea -- the absence of an ambassador to South Korea for almost a full year sends the message that he doesn't take this important relationship seriously. (Victor Cha, the Georgetown professor Trump picked for the post only last month has yet to be formally nominated for Senate confirmation.) Trump should express openness and desire for a diplomatic path, rather than demeaning those who pursue it.

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