Iran-Contra jumps to mind wherein one part of the operation was to trade weapons to Iran in order to facilitate the release of hostages held by Hezbollah in Lebanon.

The relevant quote from Reagan: "A few months ago I told the American people I did not trade arms for hostages. My heart and my best intentions still tell me that's true, but the facts and the evidence tell me it is not. As the Tower board reported, what began as a strategic opening to Iran deteriorated, in its implementation, into trading arms for hostages. This runs counter to my own beliefs, to administration policy, and to the original strategy we had in mind."

http://en.wikipedia.org/wiki/Iran%E2%80%93Contra_affair#Arms_sales_to_Iran

I'm just going to leave a reminder here not to discuss present-day politics in this subreddit, and to confine any discussion of the issue to events taking place before 1995.

Qian Xuesen was a California Institute of Technology researcher who was one of the founders of JPL. He was accused of being a Communist and was detained in the United States under house arrest for five years. Afterwards, he was deported back to China, where he became the father of Chinese rocketry. Iris Chang writes in her book "The Chinese in America" that he was swapped for several American POWs taken during the Korean War.

Under Secretary of the Navy Kimball had this to say: "It was the stupidest thing this country ever did. He was no more a Communist than I was, and we forced him to go."