Without US troops, would the North invade South Korea?

Would the United States go to war in Korea if the North launched a conventional invasion of the South, and there were no U.S. troops in South Korea to be threatened with death or capture? The answer is highly relevant if the U.S. withdraws the 23,000 troops we have stationed in South Korea, as President Trump proposed in bargaining with South Korea over trade last year. In 1950, the United States withdrew the troops we had stationed in South Korea after WWII. Secretary of State Dean Acheson said