A newly surfaced letter penned by Ronald Reagan may have foreshadowed the 40th president's transition from Hollywood Democrat to conservative icon.

In the 1946 letter, written in reply to a Russian refugee who had heard Reagan speak, the actor distanced himself from the communist hunters at work in Hollywood and Washington, but warned that Americans had to be vigilant.

“Please believe me I don’t want to be a ‘Red Baiter’ or go on a ‘witch hunt,’ but if the liberal cause is to win in the fight against native Fascism it must first stand up and be counted as opposed to communism,” the 35-year-old Reagan wrote in the two-page letter to Lola Kinel Shipman, a Polish-American author who was born in Russia and escaped the Bolshevik Revolution.

"Please believe me I don’t want to be a ‘Red Baiter’ or go on a ‘witch hunt’ but if the liberal cause is to win in the fight against native Fascism it must first stand up and be counted as opposed to communism." — Ronald Reagan

Shipman had earlier heard Reagan speak of the moral and policy failings of communism in the post-World War II world. She was moved enough to write Reagan, who replied on the stationery of his first wife, Jane Wyman.

“What I wanted to say is that if you agree with me that it is important to keep American liberalism true to its real tenets of freedoms, please do speak up for it again whenever you might be called upon to speak,” Shipman wrote. “Please make this clear and firm; you have a wonderful talent, you can rouse people and you know how to present ideas forcefully and logically.”

Following the war, Reagan became politically involved and highly supportive of liberal causes. He joined the American Veterans Committee, an organization with a goal of world peace, and was invited to fill a vacancy on the board of directors of the Hollywood Independent Citizens Committee of the Arts, Sciences and Professions, the main purpose of which was to promote the New Deal, led by President Franklin D. Roosevelt.

As Reagan became more involved in Hollywood and in politics, he became more aware of communist activity within certain groups. Nathan Raab, of the Philadelphia-based rare documents dealer The Raab Collection, said the letter shows the early signs of the transformation that would make Reagan a giant of the conservative movement.

“The seed was being planted in his mind that there are strong elements in his own party that are so different from his own, that perhaps he’ll never see eye-to-eye,” Raab said.

As Reagan began to take his anti-communism message to AVC conventions and other events, often to a chilly response, he began to second-guess his involvement in the Democratic Party, noted Raab.

The letter from Reagan is for sale, and valued at $17,500. Shipman gave the letter to a friend before her death, and the Raab Collection obtained it from him.