Two big myths persist about the United States and Vietnam. The first is that when U.S. soldiers returned from the war there, protesters spat upon them in disdain. The second is that no one vilified the Americans more than the Vietnamese, who continue to despise the United States for its behavior a half-century ago.

As U.S. President Barack Obama prepares to visit Vietnam on Sunday, the frequency with which observers have repeated both myths has risen. Conservatives are more likely to embrace the first and liberals more commonly invoke the second, but they’re both wrong. 

Consider the idea that U.S. soldiers faced hostility and scorn upon their return, which Senator John McCain (R-Ariz.) repeated last week. “That lack of welcome home is still a national shame,” McCain said. “You had 18- or 19-year-old draftees who did their duties and were literally spat upon by their fellow citizenry when they returned.”

Held captive and tortured in Vietnam for over five years, McCain is a war hero. He endured solitary confinement, regular beatings, and cracked ribs. But he is wrong about what happened to returning American soldiers.

According to a 1971 Lou Harris poll, 94 percent of Vietnam veterans reported receiving friendly homecomings from Americans in their age group who had not served in the military. Nor were they routinely spat upon, a myth that henchmen of U.S. President Richard Nixon propagated to stigmatize the antiwar movement. ...