In the latest round of saber-rattling between the US and North Korean governments, US Secretary of State Rex Tillerson laid down the well-worn line. “All options,” he said during a visit to South Korea, “are on the table.”

If he’s serious, here’s an option that never seems to get much discussion lately:

US president Donald Trump should send Tillerson to tell Yun Byung-se, his counterpart in Seoul, that the US is withdrawing its troops from the Korean peninsula by a specific date, and that after that date the US will cease to guarantee, or accept responsibility for, the South’s security.

If the Korean War was a person, it would be old enough to collect Social Security benefits. It began on  June 25, 1950 when the armed forces of the Democratic People’s Republic of Korea (“North Korea”) invaded the Republic of Korea (“South Korea”).

Coming up on 67 years later, it continues. The two Korean regimes still consider themselves at war, the US government still keeps nearly 30,000 US troops deployed along the ironically named “Demilitarized Zone” separating the two countries, and the situation remains as tense and sporadically violent as ever since 1953 when a temporary ceasefire was signed.

Today, South Korea is twice as populous and 35 times as wealthy (in terms of Gross Domestic Product) as the North, boasting the 11th largest economy in the world (North Korea ranks 113th).

In what universe does it make sense for American taxpayers to continue picking up a substantial portion of the check for South Korea’s defense from its smaller, poorer, less industrially advanced neighbor?

Once upon a time, at least briefly, this was a Republican talking point. In 2004, president George W. Bush announced his intent to withdraw thousands of US troops from South Korea over several years.

He did so in a campaign speech in New Mexico — a state he lost in 2000 by fewer votes than Libertarian Harry Browne received, during a visit intended to prevent a similar performance by 2004 Libertarian candidate Michael Badnarik. For an ever so brief moment, Bush faked a peacenik end run around both Badnarik and Democratic candidate John Kerry on the subject of North and South Korea.

Of course, it was back to business as usual, and to North Korea as all-purpose bogeyman, once Bush managed to get re-elected that November. But at least he was willing to broach the subject. Trump and Tillerson should do likewise — and then follow through.