Les Smith thought he was a U.S. citizen but learned otherwise when he applied for Social Security after turning 65.

"What a surprise," he said.

The mix-up was resolved Wednesday when Smith took his citizenship oath at U.S. Rep. Eric Swalwell's Hayward office, with his wife of 44 years sitting nearby, blinking, with tears in her eyes.

Smith moved to the United States from Switzerland with his parents when he was nine. He joined the Army in 1969, and received orders to go to Germany.

"I did not want to go to Germany. I went to my commanding officer and asked him to change my orders so I could be sent to Vietnam instead," the San Lorenzo resident said.

He was told that could not be allowed because he was a citizen of a neutral country. His commanding officer referred him to the Pentagon, where he agreed to become a U.S. citizen if he were sent to Vietnam, and he took what he thought was an oath of citizenship. He also received a Social Security number.

Smith acknowledged that it may sound odd to ask to be sent to a war zone.

"Now that I look back, I'm really not sure why I did," he said. "I came from Europe, and I didn't want to see it again. But I had an opportunity to see a place I'd never be able to see otherwise.

"If you didn't look at the war, Vietnam was a beautiful country."

Honorably discharged in 1972, he became a sheet metal fabricator and metal worker. He and his wife, Paula, raised two children, now grown.

"All this time, I thought I was a citizen," Smith said. But the Social Security Administration in February would not accept as proof his military discharge papers, which listed him as a citizen. "That was a slap in the face. It was devastating," he said.

Smith never tried to vote, which might have indicated something was amiss.

"I never had time. I was working, sometimes even Saturdays and Sundays," he said.

Once he learned of the problem and was denied benefits after he retired, he was referred to the congressman's office. He credited staff members in Swalwell's office for helping speed up his citizenship application.

With his new citizenship, he will reapply for Social Security benefits, he said. "This is such a relief," he said after taking the oath.

"Did that oath sound familiar?" Swalwell asked. "It sounds a lot like the one you took before."

Contact Rebecca Parr at 510-293-2473 or follow her at Twitter.com/rdparr1.