What 20th-century conflict was dubbed the "forgotten war" despite 54,246 U.S. deaths?

That would be Korea... this is an excellent site:

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It shou be the The Korean War.

You might want to double check.

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Yes, you are correct. The 20th-century conflict that was dubbed the "forgotten war" despite the high number of U.S. deaths was the Korean War.

To verify this information, you can follow these steps:

1. Open a web browser and go to a search engine such as Google.
2. Enter the search term "forgotten war in the 20th century with 54,246 U.S. deaths."
3. Look for reliable sources such as well-known news outlets, history websites, or official government publications.
4. Click on the relevant search results to find detailed information about the conflict and the number of U.S. casualties.
5. Cross-reference the information from multiple sources to ensure accuracy.

By following these steps, you can confirm that the Korean War is indeed the 20th-century conflict referred to as the "forgotten war" despite the significant number of U.S. deaths.