As an American, I think a better metric for outcomes of Korea, Vietnam, Afghanistan, and Iraq is: were we trading with the before the war and are we trading with them one generation after the war? The same is even true of WWII, a more important marker afterward is that we spent the rest of the 20th century trading prosperously with Japan and Germany.

Korea: the south became an economic powerhouse with whom we now trade for critical computer components and is a generally reliable ally in the region.

Vietnam: we now trade with them happily and enjoy generally productive relations, largely because they fought us for less than two decades but fought China for centuries and centuries.

Iraq: we aren't yet a generation past, but the government they have now is better than what they had under Saddam Hussein, even if it was almost immediately subverted by Iran. And jury is out on Iran because that hot war just started.

Afghanistan: we aren't yet a generation past, but very likely the most clear failure in this list. I remember thinking in high school (during the active phase of the war): "if we actually want to make a difference, we'd have to stay a century or more, and we don't have the will to do that the way the British or Russians tried to, and even they ultimately failed to make any local changes."

Europeans also need to realize that everyday Americans don't actually care about Europe very much and never truly have. It took the Lusitania to get us into World War I, Pearl Harbor (and Hitler's declaration of war) to get us into World War II, and the credible threat of the Soviet Union to keep us in Europe for decades after the war. The husk of Russia at the center of the Soviet skeleton isn't a credible threat to America, and the American reversion to the mean of isolationism began as the Cold War ended. That reversion completed sometime between 2010 and 2015. There is a new credible threat, but that is China, and even to well informed Americans Europe is slipping from their attention.

Most people in Trump's government probably don't care that much about reopening Hormuz quickly. Gas prices are only truly spiking in U.S. states where local environmental regulations have obstructed access to domestic and regional supply, and the largest of those states (i.e. California, New York) have broken against Republicans in every Presidential election (9 of them in a row) since the end of the Cold War.