[Following up on this post.]

The valor that garners a Medal of Honor has changed since the Civil War, when the award was first created. In fact, many of the ways that the Medal was previously given no longer hold. Perhaps the most obvious of these is that it is now extremely difficult–if not impossible–to get a Medal of Honor while surviving the acts of bravery. The military denies that this is an official requirement, though there is skepticism:

The U.S. military appears to have toughened its standards for bestowing the Medal of Honor, the nation’s highest award for valor in battle, to exclude troops who survive their heroic acts, a California lawmaker charged Thursday.
Either troops are “not as brave as they used to be, which I don’t believe is true,” or the criteria for the award have been amended “so that you have to die” to receive it, Rep. Duncan D. Hunter, R-Calif., told the Army’s top civilian and uniformed leaders.
Hunter’s assertion during a House Armed Services Committee hearing drew a rebuke from Gen. George Casey, the former U.S. commander in Iraq who now serves as Army chief of staff. “There has been absolutely no effort” to limit the award to troops who’ve perished, Casey said.
Five Americans, all killed in action, have been awarded the Medal of Honor for service in Iraq or Afghanistan. The total is far lower than that of past wars; 244 troops received the Medal of Honor for heroism in the Vietnam War, for example.

The last seven Medals of Honor have been given posthumously. The last MoH (I’m reasonably sure this is accurate) given to a surviving soldier, sailor, or marine went to Michael Edwin Thornton in October 1972:

Rank and organization: Petty Officer, U.S. Navy, Navy Advisory Group. Place and date: Republic of Vietnam, 31 October 1972. Entered service at: Spartanburg, S.C. Born: 23 March 1949, Greenville, S.C. Citation: For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty while participating in a daring operation against enemy forces. PO Thornton, as Assistant U.S. Navy Advisor, along with a U.S. Navy lieutenant serving as Senior Advisor, accompanied a 3-man Vietnamese Navy SEAL patrol on an intelligence gathering and prisoner capture operation against an enemy-occupied naval river base. Launched from a Vietnamese Navy junk in a rubber boat, the patrol reached land and was continuing on foot toward its objective when it suddenly came under heavy fire from a numerically superior force. The patrol called in naval gunfire support and then engaged the enemy in a fierce firefight, accounting for many enemy casualties before moving back to the waterline to prevent encirclement. Upon learning that the Senior Advisor had been hit by enemy fire and was believed to be dead, PO Thornton returned through a hail of fire to the lieutenant’s last position; quickly disposed of 2 enemy soldiers about to overrun the position, and succeeded in removing the seriously wounded and unconscious Senior Naval Advisor to the water’s edge. He then inflated the lieutenant’s lifejacket and towed him seaward for approximately 2 hours until picked up by support craft. By his extraordinary courage and perseverance, PO Thornton was directly responsible for saving the life of his superior officer and enabling the safe extraction of all patrol members, thereby upholding the highest traditions of the U.S. Naval Service.

In the 19th century, the percentage of Medals of Honor given posthumously was low. In the Civil War, it was 2.1%; the Indian Wars, 3.05%; the Spanish-American War, 0.91% (1 out of 110); the Philippine War, 0%. (There is a great oddity in the latter two. There were 110 Medals of Honor awarded during the Spanish-American War, a conflict of relatively short duration, and 6(!?) awarded during the Philippine War, which lasted nearly three years.)

This changed in the 20th century (percentage posthumous):

MoH Percentage Posthumous.jpg

Even as the percentage went up (to a high of 71% during the Korean War), the number of medals awarded went down. The following table includes wars in which more than 100 Medals of Honor were given, the number posthumous, and the percentage (statistics courtesy of here, percentages courtesy of me and Excel):

War Total Medals Posthumous Percentage
Civil War 1522 32 2.10%
indian Campaigns 426 13 3.05%
Spanish American 110 1 0.91%
World War I 124 33 26.61%
World War II 464 266 57.33%
Korean War 133 95 71.43%
Vietnam 246 154 62.60%

Or, to put it in chart form:

MoH Awarded-Posthumous.jpg

Since World War I, the number of Medals of Honor given has dropped, while the percentage of posthumous awards has jumped. Why the change? I don’t know, but I can offer some ideas as speculation. The shift echoes a shift in the American military towards increasing professionalization. The Root reforms of the first decade of the 20th century (following the Sherman reforms that created a more extensive military education system) seem to occur right at the shift point and may have influenced the giving of MoHs. The creation of lesser medals–like the Citation Star (which became the Silver Star)–created medals for valor that did not rise to the height of the Medal of Honor and may have pushed the level of valor for the MoH up to the range where death was likely. The increasing lethality of modern warfare may have had an influence on increasing the number of posthumous awards. The decreasing lethality of modern medicine–where witnesses to an act of valor were much more likely to survive the event–may have led to more reports of extreme valor may have done it. There’s room for a substantial academic study here, but in any case, while General Casey may deny that there is an official requirement of fatality to win the Medal of Honor, the unofficial criteria seem different.